As of yesterday the PLD Archive wiki was locked for editing and it has been moved to the new domain of wiki.pldarchive.co.uk.
The link on this site has been updated but if you have bookmarks saved or whatever then these will need updated too.
As usual there will likely be broken links and errors so if you happen to find any then please do let me know. There is an email link on the main page of the new wiki. Likewise, if anyone has any PLD dumps or recreations, PCB pictures or IC pictures to contribute please also use that new email address to send them in.
Channelmaniac kindly sent me some tech info he made up recently for the 054539 custom found on some Konami boards.
Here we have the pinout for the chip and also the circuit conenctions
Thanks to Channelmaniac for sharing these
Got an original Passing Shot PCB for repair, as you may know it’s a tennis game released for System 16B hardware by Sega in 1988.
Board had its ‘FD1094’ battery-backed custom CPU module which was still alive since the board booted but sound was missing at all:
These are the times when an audio probe really comes in handy in diagnosing the fault helping you to figure out the nature of the lack of sound (if digital or analog).So I fired up this tool and started to listem to various points of the audio circuit :
For first I probed the outputs of the YM3812 DAC and I got sound from them, this meant the fault was in the analog circuit.Looking at schematics I followed the path, the sound was still present on the input of the volume potentiometer :
But then it was silent on the output which gives the signal to the Fujitsu MB3733 amplifier :
Schematics shows there is nothing between the output of the potentiometer and the input of the amplifier (apart from a 10uF electrolytic capacitor that was tested as good)
Metering the amplifier I found that pin 1 ( the input which takes the signal from the potentiometer) was almost shorted to pin 11 (+12V supply), there was only 12.4 Ohm of resistance :
The amplifier was likely bad so I removed it :
And replaced it putting also some thermal silicon grease for a better heat dissipation :
I powered the board up again and the sound was back.No other issue found hence I could declare this board 100% fixed and working.
Over the last few months I’ve had tons of messages from readers of this blog asking about the lack of updates and all sorts of nice words so I think its time to address this officially here.
My interest in arcade repairs has pretty much dwindled down to nothing over the last 12 months or so and I have found myself finding a love for other hobbies which I am throwing myself into and loving them more and more.
That doesn’t really leave me with much free time for repairs and it certainly doesn’t leave me with any time to write up a detailed blog post about it either.
Right now, my official status on this is I wont be doing anymore repairs logs.
With that said I do put a lot of time and effort into dealing with PAL’s and will still be maintaining the WIKI and the blog will still stay with that too.
If the time comes that I wont be continuing with the site then it will either all be handed over to someone else that is willing to keep the information going or it will be saved and made available via other methods. I’m not going to let the last 10 years of work from myself and other contributors disappear.
Any of the other contributors can still post here if they wish and if anyone else wants to contribute then I will create an account for them too