Leaderboard

I've not done any repairs on one of these for many years. The fault was reset when paying out. After taking a quick look at the board I spotted this on the regulator board. After a couple of messages with Midibob and taking his advice on board I swapped those ones out and replaced them with these 3 new ones. Its all back in and tested and now my Autoroute pays out as it should again...😎

When you say there's a clock pulse from the 555 what frequency is it? With the diags, if it's out of limits (approx 500-550Hz) the diagnostics won't run! I think you changed all the associated components a while back if I recall so it's likely to be spot on. So what you know so far is the ROM is being read hence the 'Resetting' message on the Alpha so it's getting stuck a bit further up the initialising chain. It's likely IC6 is good as the Alpha is working as is the RAM too. This is maybe one of those occaisions were it's better to bite the bullet and start socketing the rest of the PIO's. Thinking if you've seen a coin and 'call manager' alarm it's likely that IC3 is running OK? It could then, and I emphasise COULD, be just IC4 and 5 that are suspect. I have known the 6840 be responsible for a no boot but like all these things you never know. One thing does concern me though, that's two bad joints you have discovered so far and you need to be careful you don't add anymore if you continue. Chip removal if not done correctly can make the board beyond economic repair. If you do give up don't scrap it as I can always use a duff MPU3.

Anyway I’ve got to go ku klux klan meeting to attend.

Thanks for posting an update. I look forward to the next update next year. Good luck.

Keep going as I'm sure you will get it up and running soon

Latest update… I fixed the solder joint for the T59 emitter on the top side of the board and now have continuity to 0v. Tested ex situ and it was still stuck with the display showing ‘Resetting RE 4.0’. I repeated the exercise checking the voltages within the Auto Reset circuit and although I was now getting 0v on the T58 emitter, the base voltage was wrong due to a bad solder joint at one side of R80. I then decided to check all my soldering in this circuit and spent ages checking continuity. I’m confident now that the Auto Reset circuit is functioning correctly. Even so, I have again removed T59 and R79 to disable it and take it out of the equation. So now upon reset whether auto or manual I get the reels stepping and the display gets stuck on ‘Resetting RE 4.0’. Leaving it sitting like this I have also had ‘Coin Alarm’ come up and another time ‘Refill required Call Manager’, but these may have been my fault catching pins when probing around. I’ve probed all the pins again on the 6117 RAM and IC9 and IC24 and all good. Reset line is high to all connected IC’s. Clock pulse is coming out of 555 timer and is present at IC2 and IC4. Probing pins on IC1 and IC2 there is plenty of activity, the only thing I’ve noted is with the PA and PB pins of the 6821’s IC3 – IC5 where most of these outputs are Lo and no pulsing, and some give no reading. I changed IC5 as it was socketed and I had a spare, but there was no change to my readings. So it’s still stuck but I haven’t given up just yet. I’ve decided to park it until the new year otherwise I’m liable to take a lump hammer to it. I’ll keep this thread alive until I fix it or scrap it. Next steps will be changing IC3 and IC4, then maybe IC11 and IC21. Cheers, Steve.

My favourite was save your money for driving lessons 🤣

You came back to a light hearted one year old thread to tell us you are a socialist and you want to bring back BT and British gas LMAO.

Did this a few years back. still have the glasses off this somewhere.

Came across a couple of boards recently with Memory protect boards on them. Not seen these before so I thought I'd draw up a diagram for them. It uses the same monitor chip as in MPS2, PCF1251 which is obsolete and unobtainable. All it does it uses the chip to monitor the VRAM voltage and then operate a solid state switch to break the RAM connection on pin 21 (WR).