On Wed, 25 Jan 2006 at 22:54:19, Robert Newson wrote:
(ref: <[EMAIL PROTECTED]>)
>Tony Firshman wrote:
>
>> On Wed, 25 Jan 2006 at 21:01:56, Robert Newson wrote:
>> (ref: <[EMAIL PROTECTED]>)
>>
>>>Mine's still sitting on my desk; however it isn't working at the moment (I
>>>suspect a ULA) :-(
>>>
>> What are the symptoms?
>
>Clears desk to get access to QL...
>
>It's been rather erratic when I last used it. I was trying to do some
>programming when it just kept corrupting - name table did silly things, etc
>and it was impossible to list (etc) the program on which I was working.
>
>Prior to that I had changed my GC battery and on re-insertion of GC, QL
>wouldn't work. I also had ICE ROM installed.
>
>Removed both GC & ICE and it seemed to work again. So had GC checked and it
>came back AOK.
>
>Then QL kept crashing and not even booting WITHOUT any extra peripherals -
>ie just the QL itself (it has had one personal mod *years* ago in that I
>changed (upgraded) the voltage regulator - as per instrs in QL mag [poss QL
>World]).
>
>Having just switched it on for the first time in ages, it has booted up
>without problem and is currently playing Psion Chess against itself (demo)
>in 3D Mode.
>
>I've had to resort back to my hacked (personal mod [again]) Phillips TX B&W
>TV (hacked in a Video input to bypass the demodulator which doesn't work) as
>my colour monitor died when I tried to use the QL after a long break
I wonder whether it is related to my Ferguson colour TX TV circa 1985.
The pcb was laid out to support RGB input - even with a modulator
disable pad. I zapped my RF modulator on this by dropping the disable
wire on a high voltage. It worked fine (and still is) with a
replacement module.
> (having
>finally got a replacement GC battery); the QL started playing up at around
>the same time.
Systems areOK with no GQ battery. You just lose the clock protection
etc.
>
>I suspect the last colour monitor wasn't doing the QL any good as prior to
>that monitor I had a rebadged Phillips TTL monitor (an Archimedes monitor)
>which worked fine (until it died and my brother took it to be fixed, never
>to be seen again), even when I did a dual display with a TV as well to show
>the difference in quality - the last colour monitor caused the TV output to
>visibly degrade considerably if run at the same time.
>
>I did have an odd occurence years ago when I removed the dead battery from
>the GC; on reinsertion of GC the QL didn't work and I thought it was fried,
>but it just started working again.
>
>I have just tried to re-insert the GC and it crashes on boot. Without it,
>it booted ok, so haven't tried to re-re-insert. Have subsequently tried ICE
>ROM and it has booted ok. Would poss suggest GC, but that *WAS* checked and
>found Ok - implying poss fault on expansion port of QL?
Yes indeed. I bet it is that.
Slightly bent pins can cause poor contact. It looks like GC and its
connector are OK as you have had it checked.
It could even be a pin bent right out of the way. That is very easy
with ones near the end, Typically they bend into an L shape. ie a bit
flat and the rest still straight. Often it can short against a
neighbouring pin causing the QL to fail (or crash - as you found).
If a pin is bent, then take the board out of the QL, and bend and
straighten the pin very very very very carefully - they are brittle and
you will probably only get one chance to bend it. Tweezers and
jeweller's screwdrivers will help.
I have seen (and repaired) dozens of QLs with this fault.
Of course as well do the std things - like cleaning chip legs (with hard
rubber) - 8302 is especially bad, and re-seat chips, heat sink compound
under the 5v regulator, cable from regulator to ram 5V (this was on
later boards) and mains filter. Mind you if you have a std US QL then
it will have loads of mods, including filtering components.
I think I say this and more in my QL troubleshooting guide on my web
site.
You could even bring it to the next North American QL show. Watch this
space..........
Tony
--
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