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Model 100 disk drive lead and memory

D

dominicbeesley

Member
Joined
Jul 3, 2009
Messages
21
Location
Hebden Bridge, UK
Hello,

I've had a TRS-80 model 100 + disk drives for ages but with a blown RAM chip and a broken DIL plug.

I'm about to replace the DIL plug and lead from the disk pack but would like to make it longer - is there a maximum length to this?

Re the RAM chip would it be possible to use a 6264 as a replacement with suitable adapter?

Cheers

Dom
 
The RAM chips are HD6117 parts - which I should be able to get hold of somehow. Unfortunately they're mounted on a ceramic carrier in groups of 4. I lost this carrier about 15 years ago!

I've just found a circuit diagram and it looks like it will require a bit of glue logic to get a 6264 to work - I'd hoped there might be a simple solution or somebody who could supply a replacement.

Cheers

Dom
 
I have a ROM/RAM daughter board here for an old video poker and what do I spy on it? A good old fashioned Hitachi HM6117P-3 chip sitting in a socket.
 
Thanks lads,

Its not looking too good now. It keeps crashing after a few minutes randomly with lots of random characters on the screen and lots of other wierdness. I'll try and track this down before adding a new RAM chip - it could be the other RAMs but these are soldered in so looks like it will take me a while to discover the problem.

No doubt I'll be back in due course once it has taken its turn on the workbench!

Cheers

Dom
 
I ran across a Portable Disk Drive Model 26-3808 that is in very poor condition, has some water damage on part of it. You can have it for the postage, Not sure if it's worth the shipping from Calif. to the UK though.
 
No thanks, though very kind of you to offer. As far as I know the disk drives I've got are ok its the actual laptop on its own that is misbehaving.

The way it is playing up is similar to the way it acted up when the first RAM chip broke so probably one of the others has gone.

To be honest I can't remember whether the laptop on its own was working 100% right when I last used it - that was a long time ago, about 20 years! Since then its been stored in several damp cellars and loft so is likely to have issues!

I remember I was trying to write a desktop OS for it but gave up for some reason, possibly the machine failed - I just can't remember now?!?

Anyway I'll check all the obvious things like leaky/low capacitors etc before I start trying to snip out these RAM chips!

Dom
 
Check the voltage on the internal battery. It causes a great deal of flakiness once it starts going.
 
That could well be the culprit - its looking a bit flakey. I'll order a new one as a matter of course...

I'm guessing that a NiMh replacement would work (possibly need to change the charge resistor though).

I'm guessing that the original was 3.6V - anyone know how many mAh the original had and I'll try and get something a bit bigger

Cheers

Dom
 
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