Fidelity HF4 missing valve ID please - UK Vintage Radio Repair and Restoration Discussion Forum

tracypaper · 20th May 2017, 10:36 pm

Hi all.
Trying to identify a missing valve from above mentioned player.
It has an EL84 in situ but the other valve (I assume the rectifier) is missing, it has a smaller diameter base than the EL84 and has 7 pins,
Pin 1 is connected to a red wire from the transformer and linked to pin 6,
Pin 3 links to pin 5 of EL84 and is also connected to bulb and a different wire on transformer.
Pin 7 goes to one of the 32ufs in the can.
The other two different wires from transformer go to chassis.
Also while i'm here the wire wound resistor connecting the two 32ufs in the can is reading over 1000ohm but the colours are suggesting 10? or 100ohm not too sure has it may have burnt a bit.
Cheers.
Gaz.

Peter.N. · 20th May 2017, 11:55 pm

Don't remember seeing a B7G rectifier, if it exists it would be an EZ90 or something similar.

Your smoothing resistor sounds about right, I would suggest that the red has turned brown.

Peter

Michael Maurice · 21st May 2017, 12:23 am

It sounds like an EZ90 wired for half wave rectification.

http://www.r-type.org/exhib/aaa0433.htm

Edward Huggins · 21st May 2017, 9:34 am

Yes, it will be an EZ80 (6X4) that is missing. These early Fidelitys used mains isolated amplifiers and were a better quality build than the later models.

'LIVEWIRE?' · 21st May 2017, 10:45 am

If the 'empty' Valve base is a B7G, then, surely, Michael Morris is right, the rectifier will be an EZ90 maybe wired as a Half-Wave Rectifier

tracypaper · 21st May 2017, 11:27 am

Thanks guys.
Now on the hunt for an EZ90.
Gaz.

Edward Huggins · 21st May 2017, 11:36 am

Quote:

Originally Posted by tracypaper

Thanks guys.
Now on the hunt for an EZ90.
Gaz.

Oppps - I meant EZ90, but at least got the 6X4 option right. I like these early Fidelity's, their only weakness (as with Dansettes) is the perilously small OPTX.

ukcol · 21st May 2017, 11:40 am

I believe MALC SCOTT owns an HF4 it may be worth sending him a PM for a definitive answer.

Edit: Gaz, I have two 6X4s listed in stock, If it is definitely an EZ90 (6X4) you want I will test them and send you one for the cost of postage.

electrogram · 21st May 2017, 8:55 pm

IIRC this model does not have a mains isolating transformer, just a heater transformer.

Edward Huggins · 22nd May 2017, 9:15 am

Wow, that's news to me. I have always thought the secondary was isolated.

tracypaper · 22nd May 2017, 8:39 pm

MALC SCOTT contacted awaiting confirmation reply.
Gaz.

tracypaper · 2nd Jun 2017, 8:43 pm

Valve received from UKCOL, Thanks Collin.
Amp now working.
Gaz.

20th May 2017, 10:36 pm	#1
tracypaper Octode Join Date: Aug 2010 Location: Beeston, Leeds, West Yorkshire, UK. Posts: 1,234	Fidelity HF4 missing valve ID please Hi all. Trying to identify a missing valve from above mentioned player. It has an EL84 in situ but the other valve (I assume the rectifier) is missing, it has a smaller diameter base than the EL84 and has 7 pins, Pin 1 is connected to a red wire from the transformer and linked to pin 6, Pin 3 links to pin 5 of EL84 and is also connected to bulb and a different wire on transformer. Pin 7 goes to one of the 32ufs in the can. The other two different wires from transformer go to chassis. Also while i'm here the wire wound resistor connecting the two 32ufs in the can is reading over 1000ohm but the colours are suggesting 10? or 100ohm not too sure has it may have burnt a bit. Cheers. Gaz.

20th May 2017, 11:55 pm	#2
Peter.N. Dekatron Join Date: Jul 2008 Location: Charmouth, Dorset, UK. Posts: 3,601	Re: Fidelity HF4 missing valve ID please Don't remember seeing a B7G rectifier, if it exists it would be an EZ90 or something similar. Your smoothing resistor sounds about right, I would suggest that the red has turned brown. Peter

21st May 2017, 12:23 am	#3
Michael Maurice Moderator Join Date: Feb 2006 Location: Wembley, Middlesex Posts: 7,225	Re: Fidelity HF4 missing valve ID please It sounds like an EZ90 wired for half wave rectification. http://www.r-type.org/exhib/aaa0433.htm __________________ Forum Moderator http://www.michaelmauricerepairs.co.uk/

21st May 2017, 9:34 am	#4
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,335	Re: Fidelity HF4 missing valve ID please Yes, it will be an EZ80 (6X4) that is missing. These early Fidelitys used mains isolated amplifiers and were a better quality build than the later models. __________________ Edward.

21st May 2017, 10:45 am	#5
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Re: Fidelity HF4 missing valve ID please If the 'empty' Valve base is a B7G, then, surely, Michael Morris is right, the rectifier will be an EZ90 maybe wired as a Half-Wave Rectifier

21st May 2017, 11:27 am	#6
tracypaper Octode Join Date: Aug 2010 Location: Beeston, Leeds, West Yorkshire, UK. Posts: 1,234	Re: Fidelity HF4 missing valve ID please Thanks guys. Now on the hunt for an EZ90. Gaz.

21st May 2017, 11:40 am	#8
ukcol Rest in Peace Join Date: May 2003 Location: Harlaxton, Lincolnshire, UK. Posts: 3,944	Re: Fidelity HF4 missing valve ID please I believe MALC SCOTT owns an HF4 it may be worth sending him a PM for a definitive answer. Edit: Gaz, I have two 6X4s listed in stock, If it is definitely an EZ90 (6X4) you want I will test them and send you one for the cost of postage.

21st May 2017, 8:55 pm	#9
electrogram Heptode Join Date: Jul 2008 Location: Hereford, UK. Posts: 719	Re: Fidelity HF4 missing valve ID please IIRC this model does not have a mains isolating transformer, just a heater transformer.

22nd May 2017, 9:15 am	#10
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,335	Re: Fidelity HF4 missing valve ID please Wow, that's news to me. I have always thought the secondary was isolated. __________________ Edward.

22nd May 2017, 8:39 pm	#11
tracypaper Octode Join Date: Aug 2010 Location: Beeston, Leeds, West Yorkshire, UK. Posts: 1,234	Re: Fidelity HF4 missing valve ID please MALC SCOTT contacted awaiting confirmation reply. Gaz.

2nd Jun 2017, 8:43 pm	#12
tracypaper Octode Join Date: Aug 2010 Location: Beeston, Leeds, West Yorkshire, UK. Posts: 1,234	Re: Fidelity HF4 missing valve ID please Valve received from UKCOL, Thanks Collin. Amp now working. Gaz.