UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Audio (record players, hi-fi etc)

Notices

Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

Reply
 
Thread Tools
Old 28th Jan 2023, 7:06 pm   #1
Martin63
Diode
 
Join Date: Jan 2023
Location: Folkestone Kent
Posts: 5
Default Hacker Gondalier GP42 - servicing amp

Hi - new member, first post.
I have purchased a Hacker GP42 to restore, this being only the second record player I have restored. Would consider myself competent with a soldering iron and meter, but a novice at valve technology (and most other electronic circuitry).
Have serviced the deck and have run the amp using a digital radio as input - it sounds really good with no distortion.
Where I need some help is in establishing whether I should be replacing any components whilst I have the unit apart. I have used https://www.vintage-radio.net/forum/...d.php?t=111739 as a tutorial and have checked all the resistors and the three key voltages.
1) 7 of the resistors are more than 20% out of tolerance (R1, R4, R7, R8, R9, R11, R12). Should I replace these, and what difference should I expect in performance if I do so (or will the amp likely fail in the near future if I don't?)
2) measured voltage across C8 at 235.5v, C11 £279.1v and C12 £263.8v on DMM. Presumably these are all close enough to spec?
3) DO I need to replace any of the capacitors or can I safely leave alone?

Many thanksClick image for larger version

Name:	IMG_2542.jpg
Views:	126
Size:	31.3 KB
ID:	272327
Martin63 is offline   Reply With Quote
Old 29th Jan 2023, 12:41 pm   #2
Edward Huggins
Dekatron
 
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
Posts: 7,809
Default Re: Hacker Gondalier GP42 - servicing amp

If it "sounds really good with no distortion" then why faff about with it? You may have read much about the "need" to change capacitors. Yes, there are key mains and coupling caps that may need attention in due course, but for now leave well alone!
__________________
Edward.
Edward Huggins is offline   Reply With Quote
Old 1st Feb 2023, 8:29 am   #3
John10b
Nonode
 
Join Date: Nov 2016
Location: Aberaeron, Ceredigion, Wales, UK.
Posts: 2,378
Default Re: Hacker Gondalier GP42 - servicing amp

The tutorial you refer to is very informative, and as stated the capacitors are considered very reliable. You say there is no distortion and it sounds ok, also your voltage readings, using your DMM are close enough, the original voltage reading were taken using AVO meter. So I would agree with Edward.
John
John10b is offline   Reply With Quote
Old 1st Feb 2023, 10:21 am   #4
Nickthedentist
Dekatron
 
Nickthedentist's Avatar
 
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,054
Default Re: Hacker Gondalier GP42 - servicing amp

Could we have a clearer picture, please, Martin?

The coupling capacitors we're especially interested in are just blurry red blobs in your original image

If it were mine, I would replace these two capacitors as a matter of course, and then leave well alone as Edward suggests.
Nickthedentist is offline   Reply With Quote
Old 1st Feb 2023, 11:39 am   #5
PJL
Dekatron
 
Join Date: Sep 2005
Location: Seaford, East Sussex, UK.
Posts: 5,753
Default Re: Hacker Gondalier GP42 - servicing amp

How far you want to go with restoration depends on how often you plan to use it. If you will be using it regularly I would replace the out of tolerance resistors and capacitors.
PJL is offline   Reply With Quote
Old 2nd Feb 2023, 9:47 am   #6
Michael Maurice
Moderator
 
Michael Maurice's Avatar
 
Join Date: Feb 2006
Location: Wembley, Middlesex
Posts: 6,977
Default Re: Hacker Gondalier GP42 - servicing amp

All the GP42's I've seen have had Mullard mustard coupling capacitors which should be fine. I replace the two 220K resistors on the top tag strip together with the 220R, 2.2K on the bottom tag strip and the 4 47uF electrolytic capacitors.
__________________
Forum Moderator

http://www.michaelmauricerepairs.co.uk/
Michael Maurice is offline   Reply With Quote
Old 6th Feb 2023, 9:00 am   #7
Martin63
Diode
 
Join Date: Jan 2023
Location: Folkestone Kent
Posts: 5
Default Re: Hacker Gondalier GP42 - servicing amp

Nick - do these pics of the caps help?
Click image for larger version

Name:	cap1.jpeg
Views:	63
Size:	14.9 KB
ID:	272771Click image for larger version

Name:	cap2.jpeg
Views:	62
Size:	15.6 KB
ID:	272772
Martin63 is offline   Reply With Quote
Old 6th Feb 2023, 9:30 am   #8
Nickthedentist
Dekatron
 
Nickthedentist's Avatar
 
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,054
Default Re: Hacker Gondalier GP42 - servicing amp

That's much better!

Michael, what do you think? Are those the Mullards you were referring to? They certainly look like their C296 "mustards", albeit bright red.
Nickthedentist is offline   Reply With Quote
Old 6th Feb 2023, 6:26 pm   #9
Herald1360
Dekatron
 
Herald1360's Avatar
 
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,363
Default Re: Hacker Gondalier GP42 - servicing amp

The one with visible text has LEMCO on it so not Mullard Mustards.

If they're plastic film types they should be OK.

Not sure those resistors look original? Has anyone been at it already?
__________________
....__________
....|____||__|__\_____
.=.| _---\__|__|_---_|.
.........O..Chris....O
Herald1360 is offline   Reply With Quote
Old 6th Feb 2023, 7:47 pm   #10
Station X
Moderator
 
Station X's Avatar
 
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 19,889
Default Re: Hacker Gondalier GP42 - servicing amp

Quote:
Originally Posted by Herald1360 View Post
Not sure those resistors look original? Has anyone been at it already?
That's what I thought, five band resistors. The soldering on the Lemco capacitors looks original though.
__________________
Graham. Forum Moderator

Reach for your meter before you reach for your soldering iron.
Station X is online now   Reply With Quote
Old 6th Feb 2023, 8:26 pm   #11
Martin63
Diode
 
Join Date: Jan 2023
Location: Folkestone Kent
Posts: 5
Default Re: Hacker Gondalier GP42 - servicing amp

I replaced the resistors last week! Am inclined to leave the rest alone as itís working well.
Thanks all for your help.
Martin63 is offline   Reply With Quote
Reply

Thread Tools



All times are GMT. The time now is 5:55 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2023, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.