I've had a bad day!!!...please help!

[Gerry]

In the last 72 hrs one of my Kel80s has just started to fade out and not work.
I realised that the 6AU6 was not working from time to time.
I swaped it and checked all the joints esp. on the heater links.
It still fades...then after 5mins comes back on.
I have checked the voltages....bit strange!

Pin 3 (H) to pin 4 (H) = 0dc (should be 6.3dc)
Gnd to pin3 (H) = 2.42 dc (should be 6.3dc)
" pin 4 " = 2.42 dc " "
" pin 7 (K) = 0 dc " 1.5 dc
" pin 5 (A) = 170 dc " 125dc

What could it be...the rectifier???? Or (which is very possible) am I missing something obvious?

And to top it all.....I broke the cantilever on my DL103 while this was going on....great night!!!

Any help much apprieciated

Cheers
Gerry

[Rob042]

Gerry
are the voltages around the valves ok - ie the ht .

whats the voltage coming out of the rec' and the voltage after the smoothing cap? do the the other valves light up?

What a bummer of an evening, have you naffed off someone?

Rob

[Richard]

Originally Posted by Gerry

Pin 3 (H) to pin 4 (H) = 0dc (should be 6.3dc)
Gnd to pin3 (H) = 2.42 dc (should be 6.3dc)
" pin 4 " = 2.42 dc " "
" pin 7 (K) = 0 dc " 1.5 dc
" pin 5 (A) = 170 dc " 125dc

Hi Gerry,

Sorry to hear of your woes.

When you took those voltages was KEL80 input connected to a source? If so the grid would have seen ground via a low resistance and the 2.42v to each heater pin may be normal - though I've not measured in these conditions. Did you check the other amp?

That leaves pin 7 which shows no current is flowing and pin 5 which is high confirming no/little current.

First thought is to swap the valve. If you've done this and it's the same suspect a bad cathode connection. Amp off, meter pin 7 to chassis for 331R. If it is 2k2 then R24 390R is failed/disconnected. If it's 390R the feedback loop or R29 2K2 is failed/disconnected (unlikely as volume would go high). If it's 0 both are out.

Rich

[Gerry]

Hi Rich

Thank you. I did swap valves and the fading continued. I didn't have them contected to a source as in the instructions they said not to. Needless to say I haven't checked the other amo...hassle etc, but will do a side by side comp and I will check these voltages out and report.

Managed to get a new DL103 exchange from Origin Live for £75....so feeling a bit happier!

Gerry

[andrew ivimey]

sorry to hear your news Gerry but there will be a ratioinal explanation.

It is good to see that OL have come through. Would they like any more worn out and broken 103s? Is this normal practice or did you beg and plead?

There was a chap in Spain on ebay who is doing them for about that but it would be great to source a (reliable) GB supplier.

Williamthakker in germany on ebay is doing a 103 (and loads of others) for about £85 - others cost more or less, obviously ;-)

if I had a few shekkels to rub together I'd buy one as a spare.

[Gerry]

Andrew

This is the second I've had from them at this price....it is their normal exchange price. Can't beat it really.

Williamthakker...is he ebay bsed or does he have a web site?

I've found Ortofon MC15 MKII for £125....have you ever used/heard one?

Gerry

[david counter]

I've got a MC15 II,
IMO it's a very nice cartridge, with a bouncy and detailed sound, not sterile like the MC25FL, I've never had a 103 so I can't compare them but as an entry level MC the 15 is very good