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max1227

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  1. max1227

    Value of Umax PowerMac Clone

    Yes I suppose it is! However any sort of valuation would be greatly appreciate. I presume these machines are desirable.
  2. Does anyone have an idea of the approximate value of this Umax clone?
  3. max1227

    Apple Lisa Widget Drive

    Thanks for your messages. Yes I have learnt that you can be much more forceful with these drives than one might expect. I since have acquired two more widgets and have opened up all 3. Now on all 3 brakes release and all 3 have the glass optical grating intact and stuck down. One I think has a bracket holding it in place which incidentally is also a low serial number and a 4 layer controller. The two additional widgets I acquired were also broken but I managed to fix them both. Easy cases of stuck platters and one had a faulty Z8 which I worked out through swapping boards and IC's. But that original widget (the one mentioned at the start of this thread) isn't working unfortunately. I have swapped boards and the behaviour doesn't change. Platters are find as is the glass optical grating and the heads and bearings all move freely. All in all this drive runs very quiet. It doesn't pass it's self-test and gets stuck there. No squeak-squeak just a jittering behaviour. See attached video. I will use NeoWidEx when I get a moment to switch out the working widgets with this one and will update this post in due course. IMG_1060.mov
  4. max1227

    Lisa 2/5 opinion needed!

    Thank you both for your help. A while back I ordered a ESR meter and it arrived today (took absolutely forever but I'm glad that its finally here). So I tested the capacitors C33 and C46 two capacitors involved in some shape or form from what I can tell with the +5B2 trace (I could be wrong here). Both capacitors tested fine and were good according to the meter. I then check most of the larger (in physical size) axial electrolytics on the board also and they too were fine. I then compared the readings to a working 2/10 I/O board and the values obtained were very similar. That's when I saw this... Between pin 12 and 13 (if I remember correctly) on LS109 there is a small full break in the trace. The only explanation I could think of what's that the trace is not too damaged such that after the computer has been on it heats up a bit causing the copper to expand and then make contact. After patching this trace, at the moment (I feel as though I have to stress this because the machine almost caught me out with the whole parallel connector fiasco) it's working fine now and switching on and off normally. Again I am really not sure if what I have done is correct but it seems to have done the trick for now. I am very surprised that given the visual appearance of this I/O board that only one trace was broken due to the corrosion. I realise that if left untreated it's a ticking bomb, but the boards have been treated and their functioning state hasn't deteriorated further after 4 years of ownership of this machine.
  5. max1227

    Lisa 2/5 opinion needed!

    Again silly question, are these electrolytic caps? I only have a store of surface mount electrolytics for recapping Mac logic boards which obviously wont work with the design of the Lisa I/O board.
  6. max1227

    Lisa 2/5 opinion needed!

    Thank you both for your replies. I have tested this 2/10 I/O board and you're both absolutely right. The Lisa works fine with the 2/10 I/O board powering off and on normally therefore the problem is verified to be on the 2/5 I/O board. Will all traces verified as working in the affected area on both sides of the board I'll have to wait until the ESR meter arrives to test the capacitors.
  7. max1227

    Lisa 2/5 opinion needed!

    Thanks for your reply. Just made a quick post on the forum to see if we can get a consensus. I feel this information may be of use to other Lisa 2/5 owners attempting to repair their I/O boards.
  8. Hi Lisa enthusiasts, I have a 2/5 which has I/O problems due to the corrosion and myself and a fellow member are trying to diagnose. I need to find out if the I/O board is the fault or potentially the edge connectors or traces on the motherboard. I don’t have a spare I/O board unfortunately. Is it possible to interchange a 2/10 I/O board for a 2/5? This will require use of the same 2/5 motherboard, CPU card and memory boards although the latter 2 I believe are interchangeable between any Lisa system ROMs dependant I suppose if you have the Mac XL screen mod and 800k drive. A source using the Lisa FAQ says it is but the Lite Adapter should see modifications which involve cutting traces. So if I disconnect the Lite Adapter can I do it? Has anybody tried this? Ive also read many posts on this forum that say you will destroy or damage the system if you plug in a 2/10 I/O board into a 2/5 system and since the rarity of these boards are forever increasing I would like very much to not add another dead one to the pile. Max
  9. max1227

    Lisa 2/5 opinion needed!

    Fab thank you so much! I have ordered an ESR meter the same as the one you have as I really need one that works in circuit as so many of the capacitors around the COP’s chip have corroded solder joints so I cannot easily desolder them. In the meantime I was wondering if electrically speaking a 2/10 I/O board is compatible at all with the Lisa 2/5 motherboard, CPU and memory boards? I saw a post of the Lisa FAQ which says they are but you have to make modifications to the Lite Adapter. I don’t wish to do this so if I unplug the lite adapter and leave the twiggy cables unplugged can I overcome this problem? The reason I ask is I have seen quite a few posts saying you can switch them provided you make those modifications and then a couple saying you absolutely cannot interchange the boards.
  10. max1227

    Lisa 2/5 opinion needed!

    If this is after a period of inactivity and it is left plugged in so the +5V standby is on the Lisa will always start up correctly If this is after a period of inactivity and it is NOT left plugged in so the +5V standby is off the Lisa will always startup without the soft switch being pressed. The crowbar mechanism is okay I think as to test this I adjusted the pot beyond the specification of +5V (probably not recommended) and it activated and the Lisa when tick tick tick tick when plugged in and power switch pressed. So the +5V is good and that safety mechanism is working normally. Ive tested a different PS and the Lisa behaves the same therefore I am inclined to believe the issue doesn’t lie within any of the caps in the PS. Again a silly question but how does one test the capacitors? It could be one of C52 or C46 or any of the above as I haven’t checked any of those but the traces to them are good.
  11. max1227

    Lisa 2/5 opinion needed!

    So I tested all those traces for continuity and they are all good measuring almost zero ohms. I also swapped the COP421 chip (no difference) and swapped the 6522's (no difference). Really not sure where to check next as all the traces appear to be working normally. My only thought, and again, really not sure if any of this is logical thought, is that the Lisa is always on when plugged in and switched on at the wall. Therefore that +5V is running continuously when plugged in. My Lisa without fail will not start-up correctly when plugged in and switched on at the mains after a period of inactivity. However thereafter if the Lisa has been used it will always start up properly (when the soft switch is pressed). So this implies that something is changed during operation and remains because the +5V runs continuously when plugged in and mains is on. I tested this by letting the Lisa start up and then I switched it off using the soft switch but left the Lisa plugged in at the mains for an hour. The Lisa didn't start itself up again even after the components had cooled down. I don't know if I am asking the right questions however should I suspect the transistor at Q11? It utilises the +5V and is attached to the power switch trace coming of J1-119.
  12. max1227

    Lisa 2/5 opinion needed!

    Fab thank you very much! I will check those pins for continuity Just to confirm is pin 1 and pin 2 the 7417? Your board looks quite good actually Lots of the traces around the COPS chip look the normal colour.
  13. max1227

    Lisa 2/5 opinion needed!

    This is a really silly question but where is U7F? Is it part of the COP421 chip?
  14. max1227

    Lisa 2/5 opinion needed!

    Another interesting find. The resistance of the trace between Q11 and pin 20 on the COP421 chip is reading as 15.2K, is this normal? Looking at the schematics I can’t see how this is. But as mentioned previously there is probably some component that I don’t understand how it works. But testing some other boards reveal similar readings...
  15. max1227

    Lisa 2/5 opinion needed!

    It was actually just a coincidence that the Lisa did what I said it did in my previous message. But it was a very convincing coincidence as I unplugged the parallel cable (stopped working) replugged it in (started working). I did that a couple times and it repeated the former perfectly every time. Although just retested it again and it's now exhibiting a different problem. After leaving the system alone for a while it always without fail reverts back to switching on automatically. But then after a few minutes to warm up it will start working properly again. I tested the parallel cable and connector for continuity and all pins are fine. Thats really interesting. So actually the Lisa powering off properly does confirm that quite a lot of the system is working properly. Both VIA's are socketed so I can switch them but I would have thought since the computer does work 75% of the time after warming up I think they are probably okay. I was thinking, and again, this is just hypothetical, could it potentially be either an issue with the power supply or an issue with another trace. The power supply has the electromagnetic switch doesn't it which is triggered when the +5V drifts beyond a certain range. This power supply has had the glue on the pot removed but interestingly this supply used to be in a Lisa 2/10 where I would be continually adjusting the pot to bring the +5V back into range. However in the Lisa 2/5 it never triggers - could it be that it drifts and therefore the +5V required for startup is altered? Could it also be another bad trace? I have checked a load and as black as they are they still properly conduct (could just be the green epoxy discoloured).
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