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[Debs.]

On something that age, it could be as simple as a worn power flex shorting out, but I'm no good at long distance diagnostics.

.......Heater, Cathode, Grid, Anode......or insufficient vacuum!

You forgot the top cap.

  Thermionic-amnesia!

[jereboam]

On something that age, it could be as simple as a worn power flex shorting out, but I'm no good at long distance diagnostics.

.......Heater, Cathode, Grid, Anode......or insufficient vacuum!

You forgot the top cap.

  Thermionic-amnesia!

That could be what's wrong with my valves...

[Marks DTM Calib]

Sansui....very nice (or were)

How spectacular is the fuse blow?

How good are you with a DVM?

[STMO999]

Ok. Stick a massive piece of metal in the fuse holder and see what starts to burn. That's yer faulty bit

 

[STMO999]

Ok. Stick a massive piece of metal in the fuse holder and see what starts to burn. That's yer faulty bit

 

Well? Have you tried it yet?

[jereboam]

Sansui....very nice (or were)

How spectacular is the fuse blow?

How good are you with a DVM?

What's a DVM - digital volt meter?  I can manage that, just about. 

The fuse was severely blackened, but it must have been ancient - I think I may have replaced it once before, but I can't remember why.  The replacement just blew - no significant blackening.  No bang either, although I heard a rumble from the (same vintage Sansui) speakers. 

I think the first thing I'll do is remove the case and look for burnt out bits.  Hoovering 30-odd years of dust, bugs and other detritus out of there may help a bit.

I didn't actually see it go off - I was watching something really interesting on the TV (i.e. I'd dozed off momentarily) and the I noticed the Sky box had turned off and I had no sound through my headphones.  Then I saw the light on the amp had gone out.    

[jereboam]

Ok. Stick a massive piece of metal in the fuse holder and see what starts to burn. That's yer faulty bit

 

Well? Have you tried it yet?

One suspects that, ultimately, one will have to try that solution.  But for the time being, one intends to adopt a more analytical, and thus less destructive, approach.

[Marks DTM Calib]

Pop the lid off and post a picture of the internals

[STMO999]

Ok. Stick a massive piece of metal in the fuse holder and see what starts to burn. That's yer faulty bit

 

Well? Have you tried it yet?

One suspects that, ultimately, one will have to try that solution.  But for the time being, one intends to adopt a more analytical, and thus less destructive, approach.

Chicken.

[jereboam]

It's a bit mucky, but not as bad as I expected.  I'll have a go at cleaning it after the wife has stopped watching her film and gone up to bye-byes.

Power transistors look OK, and both the internal fuses are OK.  I suspect there are more bits, possibly another board, under the metal chassis where the big transformer is mounted, but I can't play around with it until  later.

[Marks DTM Calib]

See those 4 diodes in the 1st picture just below the wire link by the screen print on the pcb saying 4A....measure them with a DVM set to resitance

[waspy]

I can see the problem, it's that fried spider in the bottom right hand corner

[Marks DTM Calib]

I actualy think its scared of your wallpaper.....

[Amigo]

Set the points gap to 25 thou!!!!

[jereboam]

See those 4 diodes in the 1st picture just below the wire link by the screen print on the pcb saying 4A....measure them with a DVM set to resitance

Once again, it will all have to wait until madam goes to bed.  I'll check them, and post the results later.

I actualy think its scared of your wallpaper.....

It's lovely wallpaper!  I chose it.     You should have seen what the wife wanted.  I could not survive a Laura Ashley living room.  Much prefer the aspirational Regency stripe.