PCB Repair Log

Post by **system11** » Thu Mar 02, 2006 9:42 am

I've dug out an old version of my PCB repair log, and added a few recent fixes I can remember. Maybe it'll be useful to anyone who also fixes their own PCBs.

http://www.system11.org/temp/repairs.html

D · Post by D » Thu Mar 02, 2006 10:01 am

Ultimarific. *printed*
Thanks for sharing. Do more people do this? Do you know of any other sites people that share their fixing skills. Are there any books?
I allways do this: ask questions when I should've just said thanks. I guess it's the excitement (and bad manners?)
Great stuff

Post by **Dave_K.** » Thu Mar 02, 2006 4:45 pm

Thank you bloodflowers! Great info here.

Stefan_L · Post by **Stefan_L** » Sun Mar 05, 2006 12:05 pm

Actually i already had the following address in my bookmarks:
http://homepage.ntlworld.com/jamesg22/repairs.html

It was very helpful for my Hammerin Harry (M81) wich had wrong colours on the sprites, you had written about a Dragon breed with the same problem and my HH had exactly the same cause of problem... a broken resistor array at the KNA91h014 chip

It was impossible to see but it cracked up when i touched it, see pic:

I do also have the X-Multiply problem mentioned on you page, minor corrupted background graphics... but i have not find any other M72 bottom board with same ram-speed to really see if thats the problem.

D · Post by D » Sun Mar 05, 2006 9:02 pm

I too have that same problem with the hammerin dude.
It says something like:
RAM NG bad upon starting up.
Some colors are a little off.
Something that helps is after it's all power up.
Turn power off and 5 seconds later turn power on again. Some (but not all) colors are correct now. I'll start digging deeper soon. I'd love to hear your findings on HH.

yaniktheyak · Post by **yaniktheyak** » Mon Jul 16, 2012 11:47 am

Hi
I'm new to this board, and found this thread through Google.
I have an original R-Type2 board M84, which works, all but the colors (original fault No Red at all)
I tracked down a burned out resistor array, and I was unable to find a replacement for it, so made one up to test with.

Having tested it last night I now have Red back, but it is not always in the right place

I have no idea how the RA burned out, but I'm guessing it could have damaged the IC (IC62) next to it.
On my board the numbers are scrubbed off the chip, but it looks the same as the one in your RType M72 board (I know they are similar).

Here is a picture of the defective display:-

Does anyone think changing this chip might solve the problem?
Does anyone have any advice on how to remove and replace a surface mount chip like this (I'm guessing I need more than a soldering iron?)

And finally:
I just wondered if anyone had a replacement KNA91H014 that I could buy, or had a broken board with one on they'd like to off load.
Also wondered if anyone had a spare RA (470ohm 7 pin, R2R Ladder) RA15 they might want to sell?

I'm UK based. I'd also consider finding someone who could fix this for me (for a fee obviously)

Thanks

yaniktheyak · Post by **yaniktheyak** » Mon Jul 16, 2012 1:57 pm

Just found, asked and had on offer from a UK repairer (IronGiant) off this board to fix it. Which is a great start

Also found some tips on how to remove a surface mount IC (channelmaniac). But it sounds a little scary to me (I'm a software guy

)
Should have had a better look around before I posted.

But that still leaves.....If anyone has, or knows where I might get those 2 parts that'd be great!!

Post by **system11** » Mon Jul 16, 2012 8:15 pm

It's probably the resistor array, I've not seen them burned out before but I've seen a fair few that were physically damaged. I have some trash M72 mainboards in the garage somewhere, I can try to find you a freebie spare before you have to pay for a repair. Give me a day or so.

yaniktheyak · Post by **yaniktheyak** » Mon Jul 16, 2012 11:20 pm

That'd be great

Thanks!!

mastercello · Post by **mastercello** » Tue Jul 17, 2012 5:44 am

system11 wrote:It's probably the resistor array, I've not seen them burned out before but I've seen a fair few that were physically damaged. I have some trash M72 mainboards in the garage somewhere, I can try to find you a freebie spare before you have to pay for a repair. Give me a day or so.

If you could send me a trash M72 bottom board, that would be excellent!

Obviously would pay you something for it.

channelmaniac · Post by **channelmaniac** » Wed Jul 18, 2012 3:02 pm

What's the part # on the resistor array? You can probably get a replacement from Farnell in the UK if you know the value/layout of the resistors and the part # on it can help determine it.

RJ

yaniktheyak · Post by **yaniktheyak** » Wed Jul 18, 2012 7:48 pm

It is RA15 on the board and says 10L471G on the component.
I have established it is likely to be a 470ohm 5 bit R2R ladder.
Used for D2A conversion.
This is the layout :

I've searched high and low, but to no avail.

channelmaniac · Post by **channelmaniac** » Thu Jul 19, 2012 2:15 am

Seems everyone I've checked with has obsoleted the part... Bourns, muRata, etc..

Here's the muRata part #: RGSD10L471G

yaniktheyak · Post by **yaniktheyak** » Thu Jul 19, 2012 11:33 pm

System11> Any luck finding those boards

channelmaniac · Post by **channelmaniac** » Fri Jul 20, 2012 2:52 am

No luck here... Maybe when I go prowl silicon valley in sept...

yaniktheyak · Post by **yaniktheyak** » Sun Jul 22, 2012 9:36 pm

Thanks for trying.
I'll keep looking.

Cheers
Ian

Post by **system11** » Wed Jul 25, 2012 9:47 pm

Finally moved enough machines around in the garage to get to the boxes, found one - PM me your address.

yaniktheyak · Post by **yaniktheyak** » Sun Aug 12, 2012 8:48 am

Just got outbid on a broken Rtype2 board on eBay.
That'd have helped with any spares - Gutted

Have you had a chance to post the part yet ?
Cheers

necroscope · Post by **necroscope** » Thu Aug 16, 2012 12:18 pm

system11 wrote:I've dug out an old version of my PCB repair log, and added a few recent fixes I can remember. Maybe it'll be useful to anyone who also fixes their own PCBs.

http://www.system11.org/temp/repairs.html

I must have come across this repair log at least 10 times searching for a fix for my black dragon pcb this is the exact symptom mine has,

Black Dragon Character falling through scenery (scenery being mis-drawn I think) Seemed like ribbon cables at first, but eventually proved to be a heat related issue on the video board. Took a short cut with this one, I had a sort-of working Black Tiger set with a bootleg CPU board and original video board. Simply swapped the video boards and ROMs around - fixed.

As i was reading it i was quite exited that you had the same problem as mine,and then you cheated,

yaniktheyak · Post by **yaniktheyak** » Sun Oct 07, 2012 11:29 pm

system11 wrote:Finally moved enough machines around in the garage to get to the boxes, found one - PM me your address.

Thanks for sending that RA. Very much appreciated.
I fitted it last night, but alas it seems there is more to the problem than just that component

I wonder if the surface mount chip KNA91... Is also damaged.

There is no way I have the skill to fit that, but if I could buy that chip off you, it might make it easier to find someone to repair it!

Thanks again for trying.

yaniktheyak · Post by **yaniktheyak** » Wed Mar 13, 2013 12:26 am

Managed to find a slightly faulty Major Title board on eBay as a donor for the SMT palette chip.

Decided there was no way I could do the transplant myself!

Many thanks to IronGiant for repairing my R-Type2 boardset!!
All working again. Very reasonable price and a very fast turn around.

That's my evenings entertainment sorted for a while

shmups.system11.org

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