Leaderboard

tony (amot) gave me the machine manual and schematic to scan in and make available to you all so i have its now in downloads :

I haven't done a write up on on Ace board for a while so being as I had three in at once I thought it worth doing. All boards were listed as dead (no boot) and as is usual with this tech battery corrosion gets in to all the chips, transistors, small caps and resistors in the bottom left corner. The PSU connector also suffers and becomes intermittent at best and more or less open circuit at worst. On first inspection they don't look too bad but as soon as the fingernail test is done most of the resistors popped their leads out! The small caps have usually disintegrated. The first thing to do is remove all the suspect components, anything with corroded legs and renew not forgetting any missing or broken caps. The next thing is continuity of the tracks under the battery. They might look good until you clean them up and that's when you end up with this.... So it's out with the garden labels and cut up some track to fit, along with the odd rivet and finsih off with a bit of green mask.... All three boards needed similar treatment. The next thing was the PSU connectors as they were badly contaminated.. Luckily these are still easily available unlike the MPU3 ones. So once we get to this stage we are ready to start fault finding!! On power up they all came out of reset which is a first. Of course after that nothing! The first thing I noticed... I subsequently found the whole ROM set was bad, luckily the set in one of the other boards was good and I now have one board working OK. On the other boards one appears to have a dead CPU ie no Address or Data activity but it's not the CPU?? A bit more head scratching to come on that one methinks. The last board tries to boot but fails and it has at least two bad chips and possibly more. More of this when I crack it. The resistor count so far is around 30+ per board, numerous transistors and small caps. The silicon count will no doubt increase on the two remaining bad ones. I'm seriously thinking about taking to drink.

Yes it's the big diode. Usually when it fails it stays short circuit, and the fail is down to age not over voltage. Having said that I have had one that was ok when cold then leaked after a while. It got so hot the solder join looked like a bad joint. For the cost of it I just replace by default to avoid problems later.

IM far from up to alot of you guys levels, but i want to learn out of interest more than anything. I picked up 3 mod 2 mpu board of ebay cheap to practice on , & to my surprise after after cleaning them up removing the battery ect, all 3 booted & worked. I've just got to set up the mag light and temp controlled soldering iron and im away . im limited to what i can test & any help greatly appreciated ive forget more than i know lol, But in keeping with the MPU mecca im attempting my own MPU repairs Gulp Board 1 blew c55 Tant cap (magic advice) so ordered some to replace with

I was thinking you may have mixed them up. Just watch your decimal point 0.01 is 10,000pf (to much). The .001uF you should find on Ebay I'm sure or there's always the usual big suppliers.

im in same boat, maybe this thread will help you a bit. save the pain.

Nothing to see here - move along please!

Haha what do you mean ‘“when the psu’s start going wrong’”? They already do!! Often!! From no 24v from them, to them going BANG!!! There bad already!!!! No chance of fixing them either!! Throw away jobs!!!

Yeah done thanks mate.

I did not bother going any further, but it seems to me mpu5 used to be very reliable but the older it gets the more problems it is getting and definitely not likely to be that reliable in the future I think!

yup! well that's what I found, I presume the arching which causes the cap to glow red hot did chips in as well, seen a few like it and none ever worked again after that

yup and when they do go on mpu5 the boards never works again I have found! here is one that's blown the tants earlier!

Fill the solder pad at Q3. No solder there

Just look at my impact thread, I have done a good few on that thread which lots are common to a lot of the cards

Crusty tracks too between S60.3 and the cpu, are you sure all the tracks are good under the cpu socket as they do get eaten away quite a bit in that area

Still some tracks to do in my opinion

Tracks to the left of s61.6 look boarder line but maybe just the picture. Did you measure resistance or just listen for the beep on the multi meter? Listing isn't always good as boarder line tracks can still beep depending on what resistance the meter cuts the beep. Did you replace the sockets with new. Also could be the TVs diode. I replace them by default.

looks to me like bad tracks

Thats what I said.. unless 2 + 1 does not make 3 !!

so back to the board this thread was started on, not much done tonight as it has not been that warm in the workshop and could not be arsed! so the known bad track to the ram fixed, BUT also in total 4 links put in as yes there was more tracks rotted away! I am really finding the stereoscope very useful at spotting and repairing the tracks now I have one!!

Chico the Bandit was a Dutch game, set on the market by "Hobea International Trade B.V." The license is dated on 10 january 1994.