BT Cheetah similar to LO3000 - Repairing.

For service and support with i-Telex, its components and teleprinters in general

Topic author
M1ECY
Rank 7
Rank 7
Beiträge: 77
Registriert: Fr 11. Aug 2017, 13:13
Wohnort: Hitchin Hertfordshire, UK
Hauptanschluß: 459724

Re: BT Cheetah similar to LO3000 - Repairing.

Beitrag von M1ECY » Mi 27. Dez 2017, 23:00

Hi Patrick,

Yes, I hope the same.

It will be interesting to see if the CPU cards in the Lo3000 are the same as in the Cheetah.

I might be able to source a replacement processor, but I am hesitant to order parts until I have a better idea of what is going on.

Do you know if there were extender cards made for the Lo3000, to allow tests to be carried out on the boards?

Sean

Benutzeravatar

Patrick
Rank 9
Rank 9
Beiträge: 224
Registriert: Mi 1. Jun 2016, 19:46
Hauptanschluß: 54577 aros d

Re: BT Cheetah similar to LO3000 - Repairing.

Beitrag von Patrick » Mi 27. Dez 2017, 23:10

Hi Sean,
I'm not aware of any extender cards. Would be helpful to build one to get better access to measure. The connectors are standard parts which should be easily available. Which supplier do you have in the UK (except RS) ?
Patrick
i-telex (T1000S): 54577 aros d


Topic author
M1ECY
Rank 7
Rank 7
Beiträge: 77
Registriert: Fr 11. Aug 2017, 13:13
Wohnort: Hitchin Hertfordshire, UK
Hauptanschluß: 459724

Re: BT Cheetah similar to LO3000 - Repairing.

Beitrag von M1ECY » Do 28. Dez 2017, 07:56

Yes, I think I can source the connectors - will take a look, and make a set of extenders up.

Think there may be an order with Richelt about to happen - they are better value than RS!


Topic author
M1ECY
Rank 7
Rank 7
Beiträge: 77
Registriert: Fr 11. Aug 2017, 13:13
Wohnort: Hitchin Hertfordshire, UK
Hauptanschluß: 459724

Re: BT Cheetah similar to LO3000 - Repairing.

Beitrag von M1ECY » Do 28. Dez 2017, 11:23

Connectors ordered - will make up a pair of extender cards.

Now on the hunt for a processor - this one is dead.

Sean


Topic author
M1ECY
Rank 7
Rank 7
Beiträge: 77
Registriert: Fr 11. Aug 2017, 13:13
Wohnort: Hitchin Hertfordshire, UK
Hauptanschluß: 459724

Re: BT Cheetah similar to LO3000 - Repairing.

Beitrag von M1ECY » Mo 1. Jan 2018, 12:39

I have now made the extender cards, this will make checking the boards in circuit so much easier.

Luckily, there was a good supply of Eurocard connectors on eBay UK.

I have found a UK source of spare processors, so one is on order.
Du hast keine ausreichende Berechtigung, um die Dateianhänge dieses Beitrags anzusehen.


Topic author
M1ECY
Rank 7
Rank 7
Beiträge: 77
Registriert: Fr 11. Aug 2017, 13:13
Wohnort: Hitchin Hertfordshire, UK
Hauptanschluß: 459724

Re: BT Cheetah similar to LO3000 - Repairing.

Beitrag von M1ECY » Mo 1. Jan 2018, 16:48

A couple so pics of the story so far
Du hast keine ausreichende Berechtigung, um die Dateianhänge dieses Beitrags anzusehen.


Topic author
M1ECY
Rank 7
Rank 7
Beiträge: 77
Registriert: Fr 11. Aug 2017, 13:13
Wohnort: Hitchin Hertfordshire, UK
Hauptanschluß: 459724

Re: BT Cheetah similar to LO3000 - Repairing.

Beitrag von M1ECY » Di 2. Jan 2018, 21:32

Work carries on slowly.

I have replaced the processor on the CPU board, now the green status LED is illuminating again.

I also traced a bad 74s04 chip on the smaller board that sits behind the CPU - this was replaced with a 74LS04 that I had laying in stock.

A couple of times this evening the bell sounded in the machine, and the screen rubbish changed, but nothing else has happened.

Awaiting a logic probe to have a look around the CPU to find out what is going on.

Antworten