Tehkan World Cup PCB Repair

[Purity]

I bought a fully working Tehkan World Cup PCB off eBay, and it turned out to be faulty.

The seller refused to do anything about it, and blamed me for the fault, saying that it was fully working when it left him, only a couple of days earlier.

Anyway...I wanted to keep the PCB so went about trying to fix it.

Firstly I found that the resonator on the top board was broken. Thanks to Ben76 I found a replacement, fitted it, and this fixed an issue with the background sounds.

Next up the sprites were just lines on the screen, and I assumed that this was probably a counter issue on the lower board.

There are no schematics for this board, so I didn't have much to go on. However I found two LS161 counters that had issues by piggybacking known working chips over the top.

Sprite problem solved and fully working Tehkan World Cup!

I'll post pictures later of where the 3 items are located, as there are no location markings on the PCB

Purity2014-09-24 18:41:58

 

[ben76]

Nice work mate

- Ben

 

[Body pop]

I bid on that myself
Quite fancied it
Nice fix .
You should send the seller the bill for your time

 

[Purity]

I bid on that myself
Quite fancied it
Nice fix .
You should send the seller the bill for your time

The guy was recommending pcb repair services and that was pretty much it. However it is a bootleg board so would cost more to have repaired by a third party than what the board was worth.

I bought it 100% fully working, but I'd be amazed if that was true, considering what I found. Work had also been done on it before that was shoddy. It looked like someone had used a blow torch to put an Eprom socket in place

He said I broke it and it's my problem. Considering I've owned quite a number of PCB's over the years, I think I know how to treat and look after them

@Body Pop - I bet you are glad you didn't buy it now
Purity2014-09-23 18:15:50

 

[Big Phil]

So you're the one that beat me. I guess I owe you a handshake

 

[Purity]

So you're the one that beat me. I guess I owe you a handshake

A lucky escape

I really wanted the PCB. It's a bootleg one as it supports a joystick, which is handy in my case I paid over the odds for it but oh well. You don't see them come up very often

Purity2014-09-23 20:45:51

 

[ben76]

Point the seller to the repair log so show you weren't telling lies lol

- Ben

 

[Purity]

Point the seller to the repair log so show you weren't telling lies lol

- Ben

I've done that, and asked for my repair costs to be paid, which I have receipts for if he wants them.

Total I'm asking for is just over £8. I think that's fair

 

[frothmeister]

Nice work Ben.

Who was the scumbag who sold you it? I think we need to avoid him if he's selling other pcbs on ebay!

 

[silverfox0786]

I agree name and shame him

after what faults you found its impossible they occurred just in transit and yes you know how to deal with PCBs and everyone here can vouch for that

 

[ben76]

I agree name and shame him

after what faults you found its impossible they occurred just in transit and yes you know how to deal with PCBs and everyone here can vouch for that

Faults can occur by even looking at a pcb in the wrong way

its old stuff as we all know

I do find the fact the seller wouldn't entertain it a problem so I do agree if the seller doesn't sort things out with Ben then name them. Yes a rare pcb but also a faulty one when delivered and going by ebay rules Ben was entitled to a full refund but chose to fix the pcb... That there is the difference to me, obviously Ben isn't trying it on and tbh I can't believe he hadn't heard of Cricklewood

Again great fix mate well done

- Ben

 

[Big Phil]

You just do a search on Tehkan World Cup completed listings. Not really detective work

birky1138 http://www.ebay.co.uk/usr/birky1138?_trksid=p2047675.l2559

 

[Purity]

Bah, I've found further issues with this :-(

I noticed during gameplay that the players disappear, and when the opposition score they don't move correctly, so there are further faults with this

Anyway, here's what I have so far:

The bits I've replaced are labelled here:

Two LS161's

One CSB480E resonator. This caused issues with the background music, and sound during the player lineup:

Here's someone's previous work on removing an eprom and replacing with a socket:

Here's my work. I took the eprom out that contained the player data to see if that was ok and it was, but the eproms were soldered to the PCB so I had to desolder and put a socket in place like above, but I think I did a better job?

Further work to be done clearly.
Purity2014-09-24 18:42:19

 

[silverfox0786]

I bet that's annoying to find that

 

[Purity]

I bet that's annoying to find that

Yup, especially when I thought I had sorted it. I shall continue to look for the faults

 

[ben76]

Arse... sure you'll fix it mate
Nice soldering too

- Ben

 

[Body pop]

All that good work for eight quid
Sounds like a good deal
Now we know where to send our broken pcb
Collections too

I'm glad didn't keep bidding I would of got no where
With it and I didn't know it was a boot
Class game all the same .good luck

 

[Purity]

I've removed the rom labelled 7 from the PCB and fitted a socket and then powered the PCB on with the rom removed, which confirms that this is definately where the problem data is stored.

I've then tried to read it in my programmer. I can see the data, but it does not ident against any known Tehkan WC roms, and also I'm getting verification errors, which leads me to believe it is faulty.

I'll reburn a new 27256 rom, when I next see the Nadster and see if that fixes the issue.

I'm pretty sure this is where the problem is.

So a duff eprom, and two duff counters......and this was meant to be working 100%

Purity2014-09-26 21:04:32

 

[ben76]

If you have any 512's can't you just double the rom to test? I am tired atm so can't remember :/

- Ben