No picture.

About original Memotech hardware.
Steven.G
Posts: 45
Joined: 18 Jul 2020 14:03

Re: No picture.

Post by Steven.G »

Call me Mr Thicko but I've studied the diagrams of the PSU plug and I still can't decide which pins I have to connect the multimeter to!

Also thanks Martin, I did try but it's well and truly on there and I don't want to force it too hard in case something gives that shouldn't.

Steve..
User avatar
Dave
Posts: 1280
Joined: 11 Aug 2012 18:16
Contact:

Re: No picture.

Post by Dave »

Did you look at the “measurement points” section in the table?

I think it’s pretty clear - but then I wrote it :)
Steven.G
Posts: 45
Joined: 18 Jul 2020 14:03

Re: No picture.

Post by Steven.G »

OK I went for it and masked all but pins 5 and 2 which gave me a reading of 23.6, which I think is what I should get.
SO I assume the PSU is OK then. Tomorrow I'll have another go at removing the board for inspection.

Steve..
User avatar
1024MAK
Posts: 757
Joined: 24 Dec 2012 03:01
Location: Looking forward to summer, in Somerset, UK

Re: No picture.

Post by 1024MAK »

Dave wrote: 20 Jul 2020 21:58 Did you look at the “measurement points” section in the table?

I think it’s pretty clear - but then I wrote it :)
With a bit of help :mrgreen:

Mark
:!: Standby alert :!:
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer in Somerset later in the year :D

Not as many MTXs as Dave! :lol:
User avatar
Dave
Posts: 1280
Joined: 11 Aug 2012 18:16
Contact:

Re: No picture.

Post by Dave »

1024MAK wrote: 20 Jul 2020 22:41
Dave wrote: 20 Jul 2020 21:58 Did you look at the “measurement points” section in the table?

I think it’s pretty clear - but then I wrote it :)
With a bit of help :mrgreen:

Mark
The page yes, the table no - that bit was all my own work :D
User avatar
1024MAK
Posts: 757
Joined: 24 Dec 2012 03:01
Location: Looking forward to summer, in Somerset, UK

Re: No picture.

Post by 1024MAK »

Steven.G wrote: 20 Jul 2020 22:34 OK I went for it and masked all but pins 5 and 2 which gave me a reading of 23.6, which I think is what I should get.
SO I assume the PSU is OK then. Tomorrow I'll have another go at removing the board for inspection.

Steve..
If you can remove the keyboard and the video board, then (for some tests) carefully push the large capacitors aside, it’s often possible to get multimeter probes to the relevant points that need testing.

But first, see if you can get your meter probes on the leads of each of the two large capacitors (C51, C56). Use the 20V DC range (or equivalent). Report back your results.

Mark
:!: Standby alert :!:
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer in Somerset later in the year :D

Not as many MTXs as Dave! :lol:
User avatar
1024MAK
Posts: 757
Joined: 24 Dec 2012 03:01
Location: Looking forward to summer, in Somerset, UK

Re: No picture.

Post by 1024MAK »

BTW, that’s the two big cylindrical light blue things, one will have two wires coming out one end. The other will have one wire coming out each end.

Mark
:!: Standby alert :!:
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer in Somerset later in the year :D

Not as many MTXs as Dave! :lol:
Steven.G
Posts: 45
Joined: 18 Jul 2020 14:03

Re: No picture.

Post by Steven.G »

I get a reading of 13.2 on pins 5 & 3 and 5 & 4 of the PSU plug is that OK?

Steve..
User avatar
1024MAK
Posts: 757
Joined: 24 Dec 2012 03:01
Location: Looking forward to summer, in Somerset, UK

Re: No picture.

Post by 1024MAK »

Yes.

Mark
:!: Standby alert :!:
“There are four lights!”
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer in Somerset later in the year :D

Not as many MTXs as Dave! :lol:
Steven.G
Posts: 45
Joined: 18 Jul 2020 14:03

Re: No picture.

Post by Steven.G »

6.15 on C51 and 0.61 on C56.

Steve..
Post Reply