World-Designs-Forum  

Go Back   World-Designs-Forum > WAD > WAD Problems
Register FAQ Members List Calendar Gallery Today's Posts Mark Forums Read

WAD Problems For questions and answers re older World Audio Design Projects

Reply
 
Thread Tools Display Modes
  #1  
Old 1st February 2006, 08:08 PM
Gerry Gerry is offline
Senior Member
 
Join Date: Jan 2006
Location: Suffolk
Posts: 453
Angry I've had a bad day!!!...please help!


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
Reply With Quote
  #2  
Old 2nd February 2006, 09:19 AM
Rob042's Avatar
Rob042 Rob042 is offline
Senior Member
 
Join Date: Jan 2006
Location: Lovely Hampshire
Posts: 251
Default Re: I've had a bad day!!!...please help!

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
Reply With Quote
  #3  
Old 2nd February 2006, 10:29 AM
Richard Richard is offline
Super Moderator
 
Join Date: Dec 2005
Location: Notts
Posts: 4,937
Default Re: I've had a bad day!!!...please help!

Quote:
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

Last edited by Richard; 2nd February 2006 at 10:36 AM.
Reply With Quote
  #4  
Old 2nd February 2006, 10:47 AM
Gerry Gerry is offline
Senior Member
 
Join Date: Jan 2006
Location: Suffolk
Posts: 453
Default Re: I've had a bad day!!!...please help!

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
Reply With Quote
  #5  
Old 2nd February 2006, 12:10 PM
andrew ivimey's Avatar
andrew ivimey andrew ivimey is offline
Senior Member
 
Join Date: Dec 2005
Location: Bedford
Posts: 2,028
Default Re: I've had a bad day!!!...please help!

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.
Reply With Quote
  #6  
Old 2nd February 2006, 01:02 PM
Gerry Gerry is offline
Senior Member
 
Join Date: Jan 2006
Location: Suffolk
Posts: 453
Default Re: I've had a bad day!!!...please help!

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
Reply With Quote
  #7  
Old 2nd February 2006, 01:16 PM
david counter's Avatar
david counter david counter is offline
Senior Member
 
Join Date: Dec 2005
Location: south west London
Posts: 1,505
Default Re: I've had a bad day!!!...please help!

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
__________________
David
"I always wanted to procrastinate, but I just never got around to it."






Reply With Quote
  #8  
Old 2nd February 2006, 04:28 PM
andrew ivimey's Avatar
andrew ivimey andrew ivimey is offline
Senior Member
 
Join Date: Dec 2005
Location: Bedford
Posts: 2,028
Default Re: I've had a bad day!!!...please help!

williamthakker is his ebay name. He does have a 'shop' and his name is Alexander.
Reply With Quote
  #9  
Old 5th February 2006, 08:16 PM
Gerry Gerry is offline
Senior Member
 
Join Date: Jan 2006
Location: Suffolk
Posts: 453
Default Re: I've had a bad day!!!...please help!

Richard

I've tested both amps and get 326R (on both) measuring chassis to pin 7!

I rechecked the voltages on both amps and swaped valves also to check..

amp1 amp2 WAD fig

Pin 7 1.578dc 0dc 1.5dc

Pin5 103.7dc 171.7dc 115dc

h to h 6.44dc 0dc 6.3dc

Same when valves swaped over.
Any ideas?

Thanks
Gerry

Last edited by Gerry; 5th February 2006 at 08:22 PM.
Reply With Quote
  #10  
Old 5th February 2006, 08:36 PM
Ianm2 Ianm2 is offline
Senior Member
 
Join Date: Dec 2005
Location: lancs
Posts: 1,175
Default Re: I've had a bad day!!!...please help!

http://cgi.ebay.co.uk/Denon-DL-103-M...QQcmdZViewItem

http://cgi.ebay.co.uk/DENON-DL-103-L...QQcmdZViewItem

http://cgi.ebay.co.uk/Denon-DL-103-M...QQcmdZViewItem
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT +1. The time now is 06:56 PM.


Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Copyright World Designs