PC-Engine RGB AMP Modding?

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mickcris
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Re: PC-Engine RGB AMP Modding?

Post by mickcris »

Tarma wrote:
kamiboy wrote:You have soldered the green input wire to the wrong side of its input resistor. Or is that a capacitor? In any regard, I am not sure how much of an impact that err wil have.

Ooh well spotted. :)

D'oh!

I'll get that resoldered regardless and check the other wires. Anyone else got any other suggestions as to why the picture may be so bright?
has your board been recapped? It looks like it possibly has not (cant tell if those are new surface mount caps or the old ones). It could be that some bad caps somewhere on the board could be causing some sort of issue.

Also, have you verified that you have no shorts on the hu6260 where you soldered to. some pins next to the ones you pull video from have 5v on them. its possible that you have bridged some pins and are also sending that 5v through the amp.


http://gamesx.com/wiki/doku.php?id=sche ... 60_netlist
Last edited by mickcris on Mon Dec 21, 2015 10:52 pm, edited 1 time in total.
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Tarma
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Re: PC-Engine RGB AMP Modding?

Post by Tarma »

mickcris wrote:
Tarma wrote:
kamiboy wrote:You have soldered the green input wire to the wrong side of its input resistor. Or is that a capacitor? In any regard, I am not sure how much of an impact that err wil have.

Ooh well spotted. :)

D'oh!

I'll get that resoldered regardless and check the other wires. Anyone else got any other suggestions as to why the picture may be so bright?
has your board been recapped? It looks like it possibly has not (cant tell if those are new surface mount caps or the old ones). It could be that some bad caps somewhere on the board could be causing some sort of issue.

Also, have you verified that you have no shorts on the hu6260 where you soldered to. some pins next to the ones you pull video from have 5v on them. its possible that you have bridged some pins and are also sending that 5v through the amp also.
http://gamesx.com/wiki/doku.php?id=sche ... 60_netlist
The board has been recapped but I'll double check the hu6260 connections make sure there is no bridging. Thanks dude!
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Tarma
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Re: PC-Engine RGB AMP Modding?

Post by Tarma »

RGB32E wrote:Tarma, the AV-DRIVER can be configured to output the right video signal voltage levels for PC Engine / TG16 RGB mods. The output from a fixed 2x gain IC like the THS7314 is too high for use with the NEC systems, and methods to drop the voltage levels are not ideal.
Ah, okay, now I understand! :o

How big is the AV driver though? I've not seen any images of it attached to an actual PCE mobo and how it can squirreled away inside the console casing.

I shall look at reflowing the solder work on my PCE Duo at work tomorrow, make sure there are no bad connections, but one thing that is good about this little amp is that it fits neatly inside the console case. That AV driver looks much larger...
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Tarma
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Re: PC-Engine RGB AMP Modding?

Post by Tarma »

looks like it may have been a solder joint drawing a voltage on the CSYNC connection. Anyway, cleaned it up and resoldered the wire to the chip. Will have to wait until tonight to see if it's done the job or not!
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RGB32E
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Re: PC-Engine RGB AMP Modding?

Post by RGB32E »

Tarma wrote:
RGB32E wrote:Tarma, the AV-DRIVER can be configured to output the right video signal voltage levels for PC Engine / TG16 RGB mods. The output from a fixed 2x gain IC like the THS7314 is too high for use with the NEC systems, and methods to drop the voltage levels are not ideal.
Ah, okay, now I understand! :o

How big is the AV driver though? I've not seen any images of it attached to an actual PCE mobo and how it can squirreled away inside the console casing.

I shall look at reflowing the solder work on my PCE Duo at work tomorrow, make sure there are no bad connections, but one thing that is good about this little amp is that it fits neatly inside the console case. That AV driver looks much larger...
It IS larger, as it has 4 channels of video amplification, a sync buffer, and stereo audio buffering. However, it is thinner as it uses tantalum instead of electrolytic capacitors. I haven't tried fitting it in a Japanese PC Engine/Core Grafx though, but was designed for use with the original PC Engine model, which is also in part why a stereo audio amplifier was included.

Image
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Tarma
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Re: PC-Engine RGB AMP Modding?

Post by Tarma »

Looks like an interesting piece of kit...

However, I am pleased to say the problem is now sorted! As mickcris suspected there was a voltage draw on one of the solder joints, in this case the wire for CSYNC. Removed the join, cleaned off the solder, reflowed the wire with a thinner coating and reattached.

I now have a beautifully crisp picture with, imo, normal levels of colour saturation and brightness.

As good as this other mod maybe, I don't see the need to add this to my Duo now that I've ironed out the teething issue with my amp install.

Many thanks to all who have tried to help, much appreciated and thanks to mickcris for hitting me up with the amp and RGB scart lead kit. I'd certainly recommend it to anyone who has not yet modded their Duo for RGB scart.
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mickcris
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Re: PC-Engine RGB AMP Modding?

Post by mickcris »

Glad you got it working. :)
moldov
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Re: PC-Engine RGB AMP Modding?

Post by moldov »

Hey everyone, just want to add my 50cents because I was having some issues with PC Engine RGB which were successfully fixed.

I have CoreGrafx (Blue Label) with attached TenNoKoe which I was using for RGB Mod implementation, because I hate those cut hole modes.

Initially I installed THS7314 mod which was described in the following discussion earlier, but picture was over saturated and over blown. I expected some solder spots on SOIP-8 adapter or somewhere else (it happened with me and my friend once we were doing NEO-GEO MVS and N64 RGB mods). I checked solder joints, removed the chip, reinstalled it again, added 100 Ohm resistors inline instead 75 Ohm - result was the same. Noisy, over saturated and bloody jailbars (which I was trying to fix by the changing capacitors as described on Tim's page) - no luck.

I decided to remove THS7314 and tried again just by getting signal directly from TenNoKoe - BINGO!!!! The picture on my OSSC is AMAZING!!!!!

No jailbars, cristal clear, just a bit of analogue noise, once I come closer to TV.

So seems that for that combination CoreGrafx and TenNoKoe THS7314 is not required. Just standard 75 Ohms inline RGB cable.
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ApolloBoy
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Re: PC-Engine RGB AMP Modding?

Post by ApolloBoy »

moldov wrote:I have CoreGrafx (Blue Label) with attached TenNoKoe which I was using for RGB Mod implementation, because I hate those cut hole modes.
Who said you had to drill any holes in the Core Grafx for RGB output? Just swap the 5-pin DIN jack for an 8-pin jack.
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