TV RGB mod thread

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K470r
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Joined: Tue Jul 21, 2020 12:27 am

Re: TV RGB mod thread

Post by K470r »

Cordial saludo

Gracias a la información compartida por ustedes, he logrado modificar mi televisor General Electric con chasis CTC177AH (chasis RCA); con el chip Sanyo LA7610

No soy bueno con la cámara y soy peor tomando fotos a CRT; como siempre, sabrán que en persona se ve mucho mejor.

Adjunto una imagen del esquema que realicé para la modificación, esta debería servir Igual para otros modelos de General Electric o RCA que usen chip Sanyo LA7610; solo se debe tener en cuenta los valores de resistencia en serie con el OSD y la resistencia a tierra del OSD. En mi caso la resistencia original en serie con OSD es de 3k y la resistencia a tierra es de 360; lo único que hice fue eliminar la resistencia de 360 y reemplazarla por una resistencia de 280 y otra resistencia de 75 puesta a tierra (280+75=355) e inyecté la señal RGB externa en medio de estas dos resistencias. Tomé los 5V para el divisor de tensión para el BLK desde el pin 8 de la EEPROM por facilidad pero se pueden tomar de cualquier otra parte que tenga 5V.



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Gracias por la valiosa información que se comparte aquí
KPackratt2k
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Re: TV RGB mod thread

Post by KPackratt2k »

maffatil wrote:HI I'm trying looking to mod a Toshiba 27A23. It has an OEC7090 and M61283 chroma chips. I know other Toshiba's with a nearly identical board layouts and the same chips can be modded, some with the switch mod and some via muxxing, but I want to attempt a mux mod.
However there seems to be some extra components in red, green, blue and blanking lines

I know from the mods on the similar tv's most of the extra components should be left, but I'm concerned about the diodes on the blue and blanking signals. Do I need to do anything different than normal if the diodes are present? I don't think the mods for the similar tv's did anything special, but I just want to make sure I don't wreck anything.
The circuitry in this set is similar to the one you have, albeit with additional components for velocity modulation which yours doesn't have:
https://sector.sunthar.com/guides/crt-r ... 7af43.html

I'd just follow along what applies to your set and see how it works out. If you do have problems, you can try removing that diode to see if it helps.
salolinkpdig8
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Signs of Digital RGB

Post by salolinkpdig8 »

What are all the likely red flags that a set is using digital RGB? I've modded several sets lately, and they end up being digital RGB so it's been a lot of wasted time.

I know to look at the jungle schematics and see if it actually says digital or RGB. I've heard that if there are no coupled capacitors in the line from osd to jungle that is another red flag (although this proved to be false on a set). And another thing I've learned to look for is the RGB voltage going into the jungle. If it's like 7 volts that's another sign it's digital RGB.

Or if anyone has anything to add to this I would really appreciate it.
crts sure are fun.
maffatil
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Re: TV RGB mod thread

Post by maffatil »

KPackratt2k wrote:[
The circuitry in this set is similar to the one you have, albeit with additional components for velocity modulation which yours doesn't have:
https://sector.sunthar.com/guides/crt-r ... 7af43.html

I'd just follow along what applies to your set and see how it works out. If you do have problems, you can try removing that diode to see if it helps.
Thanks! That's one of the similar guides I found, I just wanted a second opinion before I dove in and started removing components.

Now for a second question... I would like to use the 5v from a scart cable to switch to rgb. I believe you need to put a resistor on pin 16 of the scart header before the normal 75 ohm resistor and the resistor that matches the one removed from the stock blanking line. However, I don't know how to calculate the value of this resistor, or if its supposed to be there at all. The diagram on crtdatabase.com shows a 180 ohm resistor, but I know other mods that don't use pin 16 use resistors of varying values. In short, is there supposed to be a resistor and if so how do I know what its value should be?
maffatil
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Re: Signs of Digital RGB

Post by maffatil »

salolinkpdig8 wrote:What are all the likely red flags that a set is using digital RGB? I've modded several sets lately, and they end up being digital RGB so it's been a lot of wasted time.

I know to look at the jungle schematics and see if it actually says digital or RGB. I've heard that if there are no coupled capacitors in the line from osd to jungle that is another red flag (although this proved to be false on a set). And another thing I've learned to look for is the RGB voltage going into the jungle. If it's like 7 volts that's another sign it's digital RGB.

Or if anyone has anything to add to this I would really appreciate it.
It's not a constant rule, but a lot of sets that have components like transistors in on the RGB lines use digital RGB.
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NewSchoolBoxer
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Re: TV RGB mod thread

Post by NewSchoolBoxer »

I monitor the RGB mod scene from the side since it's electrically interesting to me even though I don't have a desire to do it myself. I think this context is important in case I'm overlooking something or my points I'm about to make were already made 50 pages ago.

So I looked at the resistor calculations. I strongly agree about using diodes and 1N4148 is cheap and popular and I use it too. That said, I think using 0.7V as the diode's forward voltage aka voltage drop in actual circuit calculations for any/all CRTs, and not just back of the envelope estimates, is ignorant and potentially harmful:
Spoiler
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The voltage drop of a diode is a function of current and temperature. At room temperature and current in the low milliamps, it's pretty close to 700mV. But power hogging CRTs don't run at room temperature and the OSD chip's RGBI output current absolute max is 1mA on the datasheets I browsed. Best chart I could find from 1N4148 datasheets:
Spoiler
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I like that the Mux doc sample calc has 0.64mA = 640uA. That yields 600mV at room temperature. One JVC model lists 500uA for the OSD current, which translates to 550-600mV. Sure seems that 700mV is always too high.

So what's the impact? Going with 6800 ohms from the Sharp CRT thread I found on Reddit, this writeup and using the too high 0.7V denoted 0.7d:

Code: Select all

 (0.7 * (6800 + 75) - (75 * (5 - 0.7d))) / (5 - 0.7d - 0.7) = 1247Ω
The other 0.7V values are the chroma peak and OSD voltage. 1300Ω is a common resistor value and listed on the Mux doc but 1250Ω exists at 1% tolerance for 69 cents.

Using a more realistic 0.55V:

Code: Select all

(0.7 * (6800 + 75) - (75 * (5 - 0.55))) / (5 - 0.55 - 0.7) = 1194Ω
1200Ω is a common resistor value. How lucky!

Using the doc and 1250Ω, you think the OSD chip is feeding the jungle chip ~0.70V but with a 0.55V diode drop, it's 0.73V. Or 0.75V with the recommended 1300Ω. Worst case about 0.77V given the 5% tolerance. Exceed the rated 0.7V by 7-10%, I think that's really pushing it but I never tried overvolting a CRT.

----------

The tl;dr is:

-I think the 0.7V diode voltage drop should be 0.55V with a note explaining that it's just an estimate.
-The voltage/current/temperature chart from a 1N4148 datasheet should be shown. Could be a more useful or easier to understand one than what I spent 10 minutes to find.
-I'm critical of acting like resistors only exist in 1.1x value increments and stating to use 5% tolerance. Seems like CRT modding is many people's first electrical project. Even if standard resistor values at 5% tolerance work okay, maybe the next project is a low pass filter where 5% parts aren't going to fly. At least suggest 1% but say that 5% is acceptable.
-Is there a typical CRT temperature for the jungle chip? Could narrow down the diode voltage drop. I see 70°C max operating temperature for OSD chips.
MarkOZLAD
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Re: TV RGB mod thread

Post by MarkOZLAD »

NewSchoolBoxer wrote: -I'm critical of acting like resistors only exist in 1.1x value increments and stating to use 5% tolerance.
The mux spreadsheet uses standard available resistor sizes. There is a lookup table in there. It DOES NOT assume that resistors are only available in 1.1x increments.

The mux spreadsheet also tells you an exact resistor calculation, the "standard size" calculation is only there for convenience. You choose whatever resistors are available to you. In my experience the ones that will be available will be the ones in the list...
NewSchoolBoxer wrote: Exceed the rated 0.7V by 7-10%, I think that's really pushing it but I never tried overvolting a CRT.
You're not overvolting the CRT, all you are doing is feeding the jungle chip RGB over 0.7V. If you look at jungle datasheets you'll find they handle way over 0.7V on their RGB inputs. In fact many OSD's voltages are way over the 0.7V which actually calls into question the need to match the 0.7V.

5% Resistors are also what you will find in the sets from the factory....
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MarkOZLAD
OSD/External RGB Mux Diagram
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"Imagine toggle switch OSD modding a TV in 2019" - maxtherabbit
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NewSchoolBoxer
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Re: TV RGB mod thread

Post by NewSchoolBoxer »

I thought you might update the spreadsheet calculations or the signature png with 0.55V or 0.6V for the diodes since 0.7V is provably too high and arbitrarily using that in circuit design is a beginner level mistake. Instead you want to defend against any changes.

I didn't originally pay attention to the 100nF / 0.1uF replacement caps on the famous diagram spread round the web. Pulling up jungle chip datasheets, I noticed the LA7615 discussed here recommends 1uF. Earlier discussion of JVC C-13011's TA1242N shows 0.47uF even though the Japanese TA1242N datasheet has 0.1uF.

Would be helpful to note not to change the existing capacitor value where it is known, unless Voultar's page 1 suggestion is all the proof needed. A series capacitor is a high pass filter and the higher the value, the higher the time constant but less distortion of the RGB square waves.
Spoiler
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Second thing I overlooked was the inevitable horizontal shift that 6tanks on Reddit explained nicely. So the shift is not necessarily fully correctable and I don't suppose all CRTs with an OSD have an option for horizontal shift. My 10 second thought is using an all pass filter that can be adjustable with a potentiometer to add enough group delay to undo the shift.
MarkOZLAD wrote: The mux spreadsheet also tells you an exact resistor calculation, the "standard size" calculation is only there for convenience. You choose whatever resistors are available to you. In my experience the ones that will be available will be the ones in the list...
An electronics novice is going to use the values your png says to use, or what the spreadsheet says to use. The recommendation function took more Excel skills than I have, impressive that it's there and helps people. I don't understand leaving out context that tighter resistor values may exist but that's okay.

Now that I think about it, I suppose rounding up versus down or to the nearest value is a mistake. Always rounding up to a higher value that increases the output voltage above the rated voltage via voltage division would seem worse.
MarkOZLAD wrote:
NewSchoolBoxer wrote: Exceed the rated 0.7V by 7-10%, I think that's really pushing it but I never tried overvolting a CRT.
You're not overvolting the CRT, all you are doing is feeding the jungle chip RGB over 0.7V. If you look at jungle datasheets you'll find they handle way over 0.7V on their RGB inputs. In fact many OSD's voltages are way over the 0.7V which actually calls into question the need to match the 0.7V.

5% Resistors are also what you will find in the sets from the factory....
I see the pin diagrams on most jungle chips have internal diode clamping so that's super nice and not what I anticipated:
Spoiler
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If every jungle chip in a moddable CRT has diode clamping on every pin, that doesn't prove exceeding the rated voltage by any amount is safe for any/all chips. Diodes don't switch instantaneously and may not be working after 10k hours of use either. But sure, if 0.7V is expected and the datasheet shows 0.5-1.0V is within spec then you're right for that chip.

First datasheet I found showing resistor tolerances without forcing me to look up the part numbers is the PVM 20M7MDE:
Spoiler
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Most but not all values are indeed 5% and is a luxury device made for video professionals. It's also a device with 500 or so resistors where the cost increase for 1% would take justification. As would using ceramics for 1uF and 4.7uF but I see only electrolytics. The L2 does have a few 1uF ceramics.

On the other extreme, I saw Nintendo used 5% resistors on their JP-21 RGB cable for 75 ohm termination. I think a premium SCART cable doing that today would face real criticism.

I guess I'm saying what I said before, the spreadsheet should recommend 1% but say 5% is acceptable. Diode voltage drop is wrong, horizontal shift is a design flaw but my suggestions are opinions and debatable.
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maxtherabbit
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Re: TV RGB mod thread

Post by maxtherabbit »

NewSchoolBoxer wrote:Exceed the rated 0.7V by 7-10%, I think that's really pushing it but I never tried overvolting a CRT.
not even close, many bone stock devices output RGB levels beyond this
MarkOZLAD
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Re: TV RGB mod thread

Post by MarkOZLAD »

NewSchoolBoxer wrote:I thought you might update the spreadsheet calculations or the signature png with 0.55V or 0.6V for the diodes since 0.7V is provably too high and arbitrarily using that in circuit design is a beginner level mistake. Instead you want to defend against any changes.
Go ahead and publish your own work you tosser. The method I documented has worked for many people for a long time but nothing stands still, everything is worth reviewing and improving on. I'm not interested in dying on a hill defending it. If you can push the method further go for your life.

PS: I did some quick calculations and worked out that your recommendations will make three fifths of fuck all difference.
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OSD/External RGB Mux Diagram
OSD/External RGB Mux Resistor Value Table 0.7Vp-p : 0.5Vp-p

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maxtherabbit
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Re: TV RGB mod thread

Post by maxtherabbit »

MarkOZLAD wrote:The method I documented has worked for many people for a long time
Let's take a moment to appreciate just how significant this is. Originally implemented by Daewoo. Discovered by viletim all the way back in 2017. Documented and abstracted by you and syntax. Truly a tour de force of the aussies. Probably hundreds (thousands?) of TVs modded since.
SuperCan
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Re: TV RGB mod thread

Post by SuperCan »

Hello, I would like to know if it is possible to modify my Trinitron KV-21SE80A to use component video (or at least RGB) as I only have a PS2 with a component cable. I believe I have found the manual for my TV, but I am having difficulty understanding it because it lists many models at the beginning. I am unsure if the diagram on page 29 applies to my TV.
https://diagramas.diagramasde.com/otros2/kv-21se80.pdf
More information: CHASSIS NUMBER: SCC-S04M-A.

Diagram? I think
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The TV
Spoiler
Image
If you need more information just ask me.
Last edited by SuperCan on Sat Mar 25, 2023 4:40 pm, edited 1 time in total.
retrozar
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Re: TV RGB mod thread

Post by retrozar »

Hi folks, i have a bunch of smaller 8040 series PVMs that don't have RGB inputs. I'm wondering if there is a way to hack RGB into these units.

I took a look at the internals and they use the same jungle chip as the 8045q, the CXA1478S, which has RGB/Component inputs. Unfortunately the 8040 series doesn't have an OSD and handles input switching automatically. Thoughts?

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maffatil
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Re: TV RGB mod thread

Post by maffatil »

retrozar wrote:I took a look at the internals and they use the same jungle chip as the 8045q, the CXA1478S, which has RGB/Component inputs. Unfortunately the 8040 series doesn't have an OSD and handles input switching automatically.
I'll start this off by saying I am not at all an expert, but I think these might be moddable. I would think that if your PVM's don't have OSD's then the RGB input pins on the chroma chip are unused. This possibly means you could directly input RGB signals into those pins with .1uf capacitors and 75 ohm terminating resistors. The thing one thing throwing me off is the lack of a blanking pin which is most likely not there because of the auto switching. It is entirely possible just inputting RGB into the correct pins could make it switch to RGB, or it may require some other type of signal. To me pins 16 and 17 in particular indicate this may be the case, but I'm not at all sure about that.

Personally, I don't think it would hurt to try inputting the correctly attenuated signals into the RGB pins to see what happens, but I could be very wrong about this. I would try doing some more research into how exactly the auto switching is handled by the monitor; it is probably the the one thing that could make this mod easy or potentially prohibitively difficult.
_megaman
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Re: TV RGB mod thread

Post by _megaman »

Axelay_2021 wrote:I have a Panasonic CT-20G7DF and after opening it up and looking around, it looks like it uses a Mitsubishi M65580MAP (https://pdf1.alldatasheet.com/datasheet ... 80MAP.html) for it's OSD. The schematics of the Panasonic has the OSD RGB signals routing back into the chip they are generated from, so my guess is that it's a single chip system and that it cannot be modified. A search for this unit/mod returns zero info, so I'm just wondering if anyone here has experience with this CRT or if anyone has an idea on whether it's even possible to inject RGB (maybe directly into the neck?). I'm not seeing another chip on the board for video signal. Am I SOL? :(
Can this set be modified to accept s-video or is it deactivated?
mightymikey
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Re: TV RGB mod thread

Post by mightymikey »

Hello all. I have a Sharp 13J-M100, RGB moddable according to this excellent write-up:
https://crtdatabase.com/crts/sharp/sharp-13k-m100b

I would very much like to add s-video while I'm in there doing the RGB mod, if possible. I notice the jungle chip (IX2933CE) has Y and C inputs (pins 43 and 45), but the composite jack runs to "ext video in" (pin 39).

I don't exactly understand the circuit, but here is my best guess:
Video in from the RF modulator comes in pin 37, external composite comes in pin 39, "video out" (pin 41) sends whichever input is active to some circuitry that splits it into Y/C (is that literally a discrete/analog comb filter?), which then goes back in (pins 43/45), has sharp/contrast/bright processing done, interleaved with the OSD RGB, then split and sent out the RGB CRT OUT pins, is that about it?

Would it be possible to use some passives, maybe just standard 75 ohm input resistors to GND and .1 DC blocking caps to inject Y/C directly into the Y/C-In pins? I couldn't find a datasheet for the IX2933CE but the crt-database writeup says its nearly identical to the Toshiba TA1268N, whose datasheet (pg 9) says the signals are nominally 1.0Vp-p for Y-IN and 286mVp-p for C-IN. I do have the skill and parts/tools to design/build a signal scaler/buffer with a dual op-amp, if that is what is needed. I believe Y and C signals are typically 0.7Vp-p, is that right?
(datasheet here: https://pdf1.alldatasheet.com/datasheet ... 1268N.html)

I don't mind if its a bit complex, if I would need to build an active daughter board to do some mixing or level conversion that is no problem, but is an s-video mod theoretically possible?

Thanks for your time.

(full schematic on page 15 of the service manual:
https://ia601702.us.archive.org/14/item ... 868835.pdf)

Schematic relevant excerpt:
Image
KPackratt2k
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Re: TV RGB mod thread

Post by KPackratt2k »

I suppose it wouldn't hurt to try to simply inject S-Video (with 75 ohm grounding resistors and 0.1uF capacitors) to the pins on the jungle chip.

If C410 is a through-hole capacitor, you can simply lift it from the buffer circuit and use it as your coupling capacitor for Luma since its value is 0.1uF.

Since there are surface mount passives on the path between the Video Output and the Chroma pins on the chip, the easiest thing to do would be to lift the Chroma pin out of circuit (either by lifting the pin or by cutting the trace that leads to the pin) and run it through the Chroma pin on the S-Video connector with the usual 0.1uF capacitor and 75 ohm grounding resistor.

If you want to, you can use a 3P3T switch to toggle the set to the stock CVBS/RF inputs, your S-Video input, or your RGB input. In this case, the switch should be connected as follows:

Pin side of the switch:
01 02 03 04
05 06 07 08
09 10 11 12

Pins 1 and 3: Luma input on IC201 (C410 leading to pin 43).
Pin 2: Existing Y/C separation circuit (the via of C410 that leads to the non-grounded side of R401).
Pin 4: S-Video Luma.
Pins 5 and 7: Chroma input on IC201 (pin 45).
Pin 6: Existing Y/C separation circuit (coming from C807 and the non-grounded side of R806).
Pin 8: S-Video Chroma.
Pins 9 and 12: No connection.
Pin 10: OSD Blanking on IC201 (pin 14).
Pin 11: +5V on the chassis through a 1000 ohm resistor.

In this configuration, one side of the switch should set the TV to its stock configuration, the center position should set it to RGB, and the other side should set it to S-Video.

The recommended voltage values for Y/C on the datasheet are the correct voltages for a typical S-Video output (1.0Vp-p for Luma and 286mVp-p for Chroma).
rejhogan
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Re: TV RGB mod thread

Post by rejhogan »

Hey all, I got a General Electric tv that I dug out from my parent's garage and in the process of doing a deep cleaning and i was wondering if this tv can be rgb modded for SCART input. The model number is 27CR620 and the chassis is CTC177AF3. I believe the jungle chip is a sanyo la7610. And im having a hard time finding info on this tv. Any help would be great, Thanks.
KPackratt2k
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Re: TV RGB mod thread

Post by KPackratt2k »

rejhogan wrote:Hey all, I got a General Electric tv that I dug out from my parent's garage and in the process of doing a deep cleaning and i was wondering if this tv can be rgb modded for SCART input. The model number is 27CR620 and the chassis is CTC177AF3. I believe the jungle chip is a sanyo la7610. And im having a hard time finding info on this tv. Any help would be great, Thanks.
There's a diagram for modding the CTC177 chassis on the first post on this page. Although the post is in Spanish, the diagram looks to be pretty self-explanatory.

https://shmups.system11.org/viewtopic.p ... 1#p1519081

Hopefully it helps you.
JoshPe92
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Re: TV RGB mod thread

Post by JoshPe92 »

Rftckeeper wrote:thank you for the response. i am new to rgb modding consumer TVs too but i have a couple years experience with arcade and pinball stuff. i have a nesrgb i am hooking up to the monitors and also a genesis rgb and an arcade pcb with jamma harness. I don't see any pots on the chassis. i have been reading a lot on here and it seems my issue is the sync delay? i have a great blanking signal on both a DTQ20U4SC and a KVS20FS12.
the problem I'm having is the sync. i tied into the s video luma on the daewoo still same result shifted way left. i don't have s video on the sony so i am going in through composite rca for sync on that one. i get a really nice looking centered black and white image of whatever signal i put into both tvs but as soon as i throw the blanking switch it looks good but shifts way left and cuts off the left side of the image. i think i understand this as the clamping?i read something about delaying the sync but I'm still scratching my head on that one. i tried ac coupling the rgb lines in on the sony but it just made the picture look shitty. It was still shifted left. i feel like I'm right there on both of these sets as the blanking and rgb are working flawlessly. i just can't get over the shifted picture. takes away from the mod imo. i successfully rgb modded a sanyo DS27800 and it looks great running arcade pcbs genesis and nesrgb. it had s video so i was able to use that luma to center the picture. i didn't have to use coupling caps or any inline resistors on the sanyo. it seems the rgb is default running until it sees a source so i dint even have to supply 5v to blanking. i just cut a jumper that must keep the jungle low and put a switch in line. only have to hit the switch if i want to use the inputs as they were designed to be used. i am happy that i was able to get at least one of the 3 I've done working well. i just can't seem to figure out the way to get my rgb signals to match my sync.or is it vise versa? i appreciate any knowledge or direction pointing to help me get to the point where i can understand exactly what needs to be done to remedy the horizontal shift. is it possible the coupling capacitors on the boards are too small? it seems those are .01 not .1
Could you please share your findings with me? Im trying to mod the same TV, Im new at this whole RGB modding, i have all the parts for a Sony BD-4A and diagram from the sanyo looks pretty similar.
mightymikey
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Re: TV RGB mod thread

Post by mightymikey »

KPackratt2k - thanks for this info, especially about s-video levels.

Can you tell from the schematic how the TV or ext composite is selected on the jungle chip? It must be selected by the microcontroller (because selection is done with the remote control), I wonder if there is a way I can digitally turn them both "off", so I could inject Y/C without having to have a big chunky mechanical switch around back. Do you know if an analog CMOS chip like a CD4066 is suitable for switching video here?

Anyhow, it might take me a while, but I will try this and I will post my findings, thanks again!
KPackratt2k
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Re: TV RGB mod thread

Post by KPackratt2k »

KPackratt2k wrote:My friend wanted me to mod a 32" Sony KV-32XBR10 TV, so I did. The funny thing is I ordered everything to make the modchip from PCBJunkie's video because I thought this set would need it due to lacking PIP and being from the same era as his set, but when I tested blanking it worked right away, so I spent more than I had to on this mod since the modchip was unnecessary for this model. Upon the first start up after the mod, I had to go into the service menu by pushing the tiny button on the input jack panel with a paperclip while pushing the power button, from there I adjusted the horizontal position and the RGB Picture (RGBP) settings in the service menu until the image looked correct. I also had to disconnect the velocity modulation cable because it was causing the incoming sync signal to be overlayed onto the RGB image.

Photo album with schematics: https://imgur.com/a/sDMaGXX
About a week after I modded this set, I also modded the 27" version (KV-27XBR10). It worked up until recently because now it shows this static when the owner tries to power it up:

Image

He has tested it without the SCART connector plugged into the header and it worked fine, so I'm thinking either the SCART connector's legs got shorted by the shield on the AV input board or the resistor between blanking and ground is shorted. I'll inspect it when he brings it over to my house to see if either of those are the case. If anyone has other ideas on what could be causing this, I'd love to hear from you.

UPDATE: It turned out there was a problem with the RGB connector on the main board of the TV, the length of the pins was too short to fit a DuPont with the original yellow connector housing in place, so I pulled out the connector housing from the connector on the main board and that made my internal RGB connector cable fit securely. I also encountered the same problem on another set with a similar chassis and had to do the same thing to fix it.

For future reference, if you're RGB modding a Sony CRT TV with the ANU-1 chassis (XBR sets from the 1989-93 time period) and plan on using a DuPont connector to connect your RGB signal to the board, I highly recommend either gently removing the yellow connector housing on the RGB header with pliers before connecting it or simply replacing the connector with a DuPont header.
Last edited by KPackratt2k on Sat Aug 26, 2023 5:40 am, edited 2 times in total.
Issac Zachary
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Re: TV RGB mod thread

Post by Issac Zachary »

Sadly my RGB and YPbPr modded Sony Trinitron BA-4 chassis has stopped working correctly too after not even that much use. There's a weird thing where as long as the screen is black or nearly black it "zapps" and the picture gets slightly smaller, then grows back and "zapps" again once about every second. When there's any color all over the screen you can see the image but it's constantly "zapping" and the image usually is warpped in the middle, more or less, towards one side.

I'm wondering if I just didn't get the PCB clean enough from the flux and dust that was on it when I put it back together, or maybe I didn't get something connected correctly. I just hope I can get it working again. Any TV repair tips or shops that are recommended (that would work on a modded TV)?
alimadhi
Posts: 27
Joined: Sun Jan 26, 2014 12:53 pm

Re: TV RGB mod thread

Post by alimadhi »

I have this cart 14" Analog no OSD just want to mod it to RGB, I open it and there is only one chip on motherboard (TA7698AP Toshiba)
Spoiler
Image
Jungle Chip: TA7698AP Toshiba
Spoiler
Image
any help please
Issac Zachary
Posts: 163
Joined: Mon Oct 23, 2017 2:54 pm

Re: TV RGB mod thread

Post by Issac Zachary »

alimadhi wrote:I have this cart 14" Analog no OSD just want to mod it to RGB, I open it and there is only one chip on motherboard (TA7698AP Toshiba)
Spoiler
Image
Jungle Chip: TA7698AP Toshiba
Spoiler
Image
any help please
Mmm. I'm no expert, but I assume the Jungle chip would need R, G and B inputs as well as a blanking input to switch to those inputs.
alimadhi
Posts: 27
Joined: Sun Jan 26, 2014 12:53 pm

Re: TV RGB mod thread

Post by alimadhi »

Issac Zachary wrote:
alimadhi wrote:I have this cart 14" Analog no OSD just want to mod it to RGB, I open it and there is only one chip on motherboard (TA7698AP Toshiba)
Spoiler
Image
Jungle Chip: TA7698AP Toshiba
Spoiler
Image
any help please
Mmm. I'm no expert, but I assume the Jungle chip would need R, G and B inputs as well as a blanking input to switch to those inputs.
I guessed it :(
Issac Zachary
Posts: 163
Joined: Mon Oct 23, 2017 2:54 pm

Re: TV RGB mod thread

Post by Issac Zachary »

alimadhi wrote:
Issac Zachary wrote:
alimadhi wrote:I have this cart 14" Analog no OSD just want to mod it to RGB, I open it and there is only one chip on motherboard (TA7698AP Toshiba)
Spoiler
Image
Jungle Chip: TA7698AP Toshiba
Spoiler
Image
any help please
Mmm. I'm no expert, but I assume the Jungle chip would need R, G and B inputs as well as a blanking input to switch to those inputs.
I guessed it :(
Sorry!

But hey! At least you have a working CRT! I hope to get mine fixed when I have time to look at it.

Personally, when I did have the RGB input mod working I did question myself if it really was worth it as it didn't seem that much better than S-Video. In otherwords, any TV with S-Video, Component or RGB I think are good choices. RGB mods are fun to do, but now that my TV has stopped working maybe it wasn't worth it.
alimadhi
Posts: 27
Joined: Sun Jan 26, 2014 12:53 pm

Re: TV RGB mod thread

Post by alimadhi »

Issac Zachary wrote: Sorry!

But hey! At least you have a working CRT! I hope to get mine fixed when I have time to look at it.

Personally, when I did have the RGB input mod working I did question myself if it really was worth it as it didn't seem that much better than S-Video. In otherwords, any TV with S-Video, Component or RGB I think are good choices. RGB mods are fun to do, but now that my TV has stopped working maybe it wasn't worth it.
You Right!
thank you
retrogamer47658
Posts: 21
Joined: Sun Apr 23, 2023 5:16 pm

Re: TV RGB mod thread

Post by retrogamer47658 »

Hey guys! Looking for a little guidance on how to mod an RF only set.

Basically, I have a Portland PT1301 (a rebadge of a Daewoo series) that I'd like to RGB mod. The one thing that's currently preventing me from doing so is that this is an RF only set; I'm not sure where to grab sync/audio from. I've confirmed that it is in fact NOT a hot chassis, but that still leaves me with the question of where I can find sync and audio. Here's the service manual for the same chassis, for anyone who's interested: https://elektrotanya.com/daewoo_chassis ... nload.html.

Thanks for your time!

Edit: probably should have included photos of the board: https://imgur.io/a/lDPwiEk
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Osirus
Posts: 214
Joined: Tue Jun 16, 2020 8:51 pm

Re: TV RGB mod thread

Post by Osirus »

retrogamer47658 wrote:Hey guys! Looking for a little guidance on how to mod an RF only set.

Basically, I have a Portland PT1301 (a rebadge of a Daewoo series) that I'd like to RGB mod. The one thing that's currently preventing me from doing so is that this is an RF only set; I'm not sure where to grab sync/audio from. I've confirmed that it is in fact NOT a hot chassis, but that still leaves me with the question of where I can find sync and audio. Here's the service manual for the same chassis, for anyone who's interested: https://elektrotanya.com/daewoo_chassis ... nload.html.

Thanks for your time!

Edit: probably should have included photos of the board: https://imgur.io/a/lDPwiEk
Quick look at the schematics:

Sync might be able to be injected into pin 42 (EXT_V_IN) of the jungle chip. It leads to an optional circuit for non-North American models that apparently included Audio and Video inputs.

The Audio inputs look like they connected to pin 51 (EXT_A_IN).
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