Lear Siegler ADM-3A Computer Terminal

[radioman]

This unit dates from the late 70's - http://terminals-wiki.org/wiki/index.php...ler_ADM-3A
I collected a lot of old computer bits when they were being thrown out at work about thirty years ago and this item has been in a box and stored in an outside shed ever since then.
On inspecting it I immediately noticed there was something far wrong with the screen...

   

Also, there was some reddish-brown coloured 'oil' dripping out of the case...
I firstly thought that the CRT had imploded but there wasn't anything rattling and on further inspection it seemed more like the 'glue' behind the faceplate was decomposing !
So, curious to find out where the oil was coming from (and wearing suitable nitrile gloves) I opened up the case for a look.
           

The oil was indeed coming from around the rim-band and given the overall condition of the whole unit, I don't think it will ever work again - in fact it looks terminal  

I was wondering if any of you have seen a CRT go like this before ?
What do you think has caused this to happen and is it dangerous to handle the CRT in this condition ?

I plan to use the case for a 'retro' project and that's why it was un-boxed after all this time.

Andy

[Refugee]

That is certainly the implosion guard turning back into the oil it was once made from.
You would need to take the rim guard apart and fit some of that clear sticky backed plastic that you stick on glass to prevent it flying all over the place should a terrorist attack take place.
I would test the tube first and then only if I wanted to run a Fidonet terminal from something old and digital.

[ppppenguin]

I don't think this is a rimband protected CRT. Looks more like a bonded faceplate with a severe case of crt cataract. Google "crt cataract", it's awell known problem and there's loads of stuff out there

[radioman]

Ah, thanks Jeffrey for telling me the correct name for this problem, I've never seen or heard about it before so not well known to me...
I had already searched online for CRT face-plate faults, oil leakage etc and found nothing !

Don't think I'll bother trying to repair this one though.

Andy

[Murphyv310]

I have seen this but never as bad. Oddly it was on a very old computer monitor pre PC days. Perhaps even the same as you're system Andy. Definitely one for the bin I'd think.

[ed731pdh]

Of interest.

https://www.youtube.com/watch?v=5l1EoMmmOcQ

[radioman]

Yes, it certainly is - thanks for posting that link.
However, it's not something that I'm going to attempt with this CRT/terminal as it's too far gone...
My plan for this unit is to replace the CRT with one from another monitor along with it's main board if it will fit in the case without too much difficulty.

Andy

[ed731pdh]

Stick a Pi or similar board in, and make it a full computer.

[davegsm82]

If you decide to scrap any part of this, please let me know, I've got one that was given to me by a friend who has since passed away. Unfortunately there is an as yet undiagnosed fault with the EHT/raster scan, as the unit powers up with a high pitched whine and nothing else. I do plan to do something with it one day, I was thinking about some sort of message system.

Thanks, Dave.

[radioman]

OK Dave, I'll keep you in mind.
I've actually got two of these terminals, both of which are in a similar state.
They are in very poor condition and I will not attempt to power them up as many of the IC's have corroded pins etc.
If/when they are scrapped I'll let you know.

Andy