Leaderboard

3 more boards have taxed the old grey matter no end. First had the usual bits corroded, triac drivers and Vbat supply transistors plus the little 1nF caps. Once done all booted and ran fine, all tests passed and left it running a soak test. I forgot to switch it off in the afternoon and only realised next morning. There it was, stuck in lamp test and on power cycle...nothing. After much head scratching everything seemed to be doing what it should do but it wouldn't boot. Then I checked the output of IC 20 (7425) and it was low! A new one restored operation. Next one failed with RS232 error but it also corrupted the Alpha display although up to the error it displayed fine? After a merry dance removing PIO chips for testing (this is a mod4 which have all the pins cropped so fitting sockets would mean all new chips). All the chips tested good so they all went back. Looking deeper into the RS232 side of things I found there was about 10v on IC5 (pin 39) which feeds the RS232 driver chip! That's definitely not right as it should be on the 5v side of the driver chip. IC26 (MC1488) had got an internal short and a replacement put things to rights. That's the brief explanation, the full one would take as long as I spent on finding it but that's another story best forgotten! And finally on to board 3. Without the RS232 plug in the diags failed with RS232 error and again corrupted on the Alpha however this time with the plug in it passed the RS232 check and then did absolutely nothing???? What the hell is going on here? As before much time was spent proving all the PIO chips were good, which they were. Checking on the the output of IC5 (pin39) again showed a constant waveform which shouldn't be there??? This was obviously being picked up by the receive circuit as a valid pulse and passed the test. Thinking it was being generated by IC5 as that is the direction of flow, with IC5 removed it was still there. Blow me there must have been an internal breakdown in IC26 again but this time generating a waveform. You couldn't make this stuff up!! With a change of chip everything started to work. Time to crack open a bottle of vino methinks.

please 😜

Thats like asking me when was the last time I had sex with my wife.......

I've got a set of glasses for this, and the reels too I think @hitthesix did a great classic on £4.80 all cash, and I've got the £4.80 token ROMs too if needed. It's gonna be a while though as they're well well buried. Something for another day mate but I'll definitely get you some good quality photo's first chance I get.

Like this one?

2 types of phoenix boards later type manuals are in downloads

It became PCP John

I'm assuming normal sound is OK? You have checked that T5 is being switched on? If it isn't you can always temporarily short that end of the pot to ground to see if that increases the volume. If it doesn't and normal sounds are OK then something wierd is going on. You'll need to put a scope on any of the ABC outputs from the 8912 chip and see what the audio levels are like there.

If you can only just hear the alarm sound and it's extremely low volume then it could be the electrolytic audio caps on the main board need looking at mate. If you have a tester you can check them and see how far out their original range they are.

Yeah I get you mate that's understandable. I have been looking for one for around 10 years myself , but only the last year I found the Facebook pages and this website. Yeah I bet it's hard work to fix and restore the old ones. And yeah I get you about the artwork , pretty much impossible to find unless you know someone scrapping one , yeah definitely keep me in mind if you get bored or want a change mate I'll pay over the odds it's the only machine I'm after to be honest lol , it's the only machine I played growing up while bunking off school , they had a £8 jackpot version in Port Talbot bus station lol

That was mine, recognised not only by the metal foot plate but that red numbering all over it too.

This next one had me going all the way to the finish line but as per usual I wasn't going to be beaten. The board was listed as 'dead, no power' and it was well and truely dead on power up even after all the usual suspect transistors and other bits had been replaced. As there was no triac test, suspicion first pointed to IC8 (68B21) but a swap out proved it to be OK. All outputs appeared to be OK from the CPU but after swapping it out, and the RAM, things started to happen! it would now boot but showed the second half of the lamps stuck on (64-127), there was also a motor drive stuck on. This was caused by two ULN2803's IC13 and 30. Unfortunately IC13 going bad had also damaged IC3 (68B21) so that had to be swapped out too. So it's all running and I'm going through all the tests OK thinking it's nearly time to wrap up when 'click' it all stops!! Hmm switch off and on and I get '6840 IC2 error' on the Alpha. In with a new one and no difference? Left it for a bit, came back and this time it's RS232 error but the Alpha is one character out of sequence?? After a few more power cycles the 6840 error comes back? Now I'm going demented as nothing is making sense! Putting my logic hat on and not my panic hat showed that it was definitley changing fault when warming up and eventually squirting freezer and warming IC5 (68B21) showed it to be the cause. After a swap out all was back running correctly. PHEW!! Mind you looking at the state of it I'm surprised it worked it all!

This next one gave me the run around. This one didn't look too bad but looks can be deceptive. In fact the rusty nuts on the 64 way cart socket should have had me running for the hills! On the first power up it booted OK but the Alpha was corrupted. Normally with the diags running you get bleep shortly after this before the main tests start running. In this case there was no bleep and nothing else happened. Concentrating on the alpha one of the links was broken between R111 and the socket PL7. There was no track damage under the battery which is the usual culprit. On the next switch on...nothing...something has died! It's the old story of pulling all the support chips till the culprit is found. Too cut a long story short all the 68B21's were removed and tested, three of these were bad. It's all a bit hazy now but at some time IC16 (74LS138) and IC19 (74LS22) were found to be bad and these were also replaced. Now it would boot again and the alpha was correct. Still no bleep though? The bleep doesn't come from the sound chip it is actually generated from IC2 the 68B40 and this was also bad. so now it bleeps and goes on to the tests but keeps failing on all sorts of things. This was due to bad connections as all the terminal pins were badly oxidised. Once cleaned it would then run OK. Next thing was to do a quick bash test, a little tap on the ROM cart and ....thank you and goodnight! In fact any movement of the cart was enough to kill it. I could see green stuff in the connector so she had to come out. A new one sorted that little problem but tapping the CPU also made it go unstable. Hmm, now where have I seen this before (MPU3 thread). In this case the CPU's legs were badly tarnished and I think one actually fell off!! In goes a new one and that was that one sorted. Sometime later the alpha died again along with the triac tests. One of my spares in IC8 (68B21) had decided it was all too much and went to meet its maker. I despair sometimes, and it wasn't a far eastern copy either. Last thing to check was the switch tests. All the right switches did all the wrong functions, give me strength. Still it's usually the two 4049 chips IC33 & 34 and so it was. I think I deserve a nice long break.🍺

I'll have a look for other Hi Lo Silver ROM but that was all that was there. I would have thought sys5 roms would have been more than 32k. Do you mean 256k? 8x32k . You really are made of magic Harry Your welcome! I did and i did try it but it didn't really do much You fucking invented it