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 4th Nov 2020, 7:38 am   #81
CrazySwede
Tetrode
 
CrazySwede's Avatar
 
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 61
Default Re: Trying to revive a Goodmans One Ten receiver

Finally some progress on the jammed tuner cap! Last night I did these two things:
1.Sprayed the cap fins with non residue contact cleaner followed by a blow out with compressed air (had the rest of the area covered with tissue to catch the overflow)
2. Added WD40 to the bearing points where the cap axle runs through the chassis.

Had been trying light oil and silicone lubricant before but this only helped for a short while.

But after the approach above I now, 12 hours later, still have an easy moving tuner that also works with good reception and stations where they should be on the scale.

Just wonder now if I should leave the wd40 in or try to clean it out and ad other type of lubrication?
CrazySwede is offline   Reply With Quote
Old 4th Nov 2020, 8:28 am   #82
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 5,087
Default Re: Trying to revive a Goodmans One Ten receiver

If it's working as you describe, then leave well alone.
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is online now   Reply With Quote
Old 4th Nov 2020, 8:43 am   #83
jjl
Heptode
 
jjl's Avatar
 
Join Date: Jan 2003
Location: Ware, Herts. UK.
Posts: 942
Default Re: Trying to revive a Goodmans One Ten receiver

Quote:
Originally Posted by CrazySwede View Post
Arthur: I'm really interested in your offer. Will post measurements tomorrow. But you think it's possible to use a 100uA meter when it seems as if this goes to 200 uA?
Yes, it is possible. You'd need to wire a resistor of identical value to the coil resistance of the 100uA meter in parallel with the 100uA meter. The resistor and the meter would then share the current equally i.e. with 200uA flowing in the combination the resistor would take 100uA and the meter would take 100uA and indicate full scale.

John
jjl is offline   Reply With Quote
Old 4th Nov 2020, 8:57 am   #84
CrazySwede
Tetrode
 
CrazySwede's Avatar
 
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 61
Default Re: Trying to revive a Goodmans One Ten receiver

Quote:
Originally Posted by jjl View Post
Quote:
Originally Posted by CrazySwede View Post
Arthur: I'm really interested in your offer. Will post measurements tomorrow. But you think it's possible to use a 100uA meter when it seems as if this goes to 200 uA?
Yes, it is possible. You'd need to wire a resistor of identical value to the coil resistance of the 100uA meter in parallel with the 100uA meter. The resistor and the meter would then share the current equally i.e. with 200uA flowing in the combination the resistor would take 100uA and the meter would take 100uA and indicate full scale.

John
Ah, that sounds good. But next question: measuring the coil resistance on the meter, is that just a matter of measuring ohms between the two connector points on the meter?
CrazySwede is offline   Reply With Quote
Old 4th Nov 2020, 9:22 am   #85
Guest
Guest
 
Posts: n/a
Default Re: Trying to revive a Goodmans One Ten receiver

The 100uA meter is just twice as sensitive if yours really is 200uA. I would have thought you would just need a series resistor. Attached pic is showing what your measured 0.17V would display on this meter with a 1K series resistor.

Arthur
Attached Thumbnails
Click image for larger version

Name:	Meter 2.jpg
Views:	19
Size:	47.3 KB
ID:	219615  
  Reply With Quote
Old 4th Nov 2020, 10:14 am   #86
CrazySwede
Tetrode
 
CrazySwede's Avatar
 
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 61
Default Re: Trying to revive a Goodmans One Ten receiver

Quote:
Originally Posted by Shuttle View Post
The 100uA meter is just twice as sensitive if yours really is 200uA. I would have thought you would just need a series resistor. Attached pic is showing what your measured 0.17V would display on this meter with a 1K series resistor.

Arthur
Looks like a nice, doable fix . As posted before, Ill do some measuring of my broken meter and get back to you regarding the offer.
CrazySwede is offline   Reply With Quote
Old 4th Nov 2020, 11:50 am   #87
Guest
Guest
 
Posts: n/a
Default Re: Trying to revive a Goodmans One Ten receiver

I should really have given you the dimensions of this meter! The front is 34.75x13.90mm and the overall depth is 32.32mm

Arthur
  Reply With Quote
Old 4th Nov 2020, 12:56 pm   #88
Chris55000
Octode
 
Join Date: Aug 2007
Location: Walsall Wood, Aldridge, Walsall, UK.
Posts: 1,537
Default Re: Trying to revive a Goodmans One Ten receiver

Hi!

The correct way to determine the resistance of your replacement signal– strength/tuning meter is as follows:–

1) Connect a 100k resistor in series with the meter and connect the meter plus resistor across a variable supply, and adjust the voltage from the supply so the meter reads exactly F.S.D;

2) Switch off the power supply and connect a pot of about 22k across the meter to act as a shunt, and switch on the supply again.

Adjust the 22k shunt pot. until the meter registers EXACTLY half F.S.D. Switch off and disconnect the power supply and shunt pot. from the meter, and then measure the value of the shunt pot. – this will be equal to the internal resistance of the meter movement!

Chris Williams
__________________
It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!
Chris55000 is offline   Reply With Quote
Old 4th Nov 2020, 7:39 pm   #89
CrazySwede
Tetrode
 
CrazySwede's Avatar
 
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 61
Default Re: Trying to revive a Goodmans One Ten receiver

Quote:
Originally Posted by Shuttle View Post
I should really have given you the dimensions of this meter! The front is 34.75x13.90mm and the overall depth is 32.32mm

Arthur
Arthur, those numbers match the meter in the Goodmans one ten! I'll pm you to continue discussion about your offer.
CrazySwede is offline   Reply With Quote
Old 5th Nov 2020, 7:34 am   #90
CrazySwede
Tetrode
 
CrazySwede's Avatar
 
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 61
Default Re: Trying to revive a Goodmans One Ten receiver

Put the One Ten together last night and must say Goodmans had a feeling for style and detail putting this together. I mean: who wants to ugly up a nice reciever with headphone connector? Of course they should be under a hatch !

Video (shared gdrive):
https://drive.google.com/file/d/1287...ew?usp=sharing

Light working:
https://drive.google.com/file/d/12I_...ew?usp=sharing

Cleaned up nicely:
Click image for larger version

Name:	IMG_20201104_200856.jpg
Views:	35
Size:	71.8 KB
ID:	219682

Time to try it in my main setup and see how it stacks up against my daily driver, a JVC vr-5535l, to do some real compairing of sound quality. Got the feeling the Goodmans will hold its own well...
CrazySwede is offline   Reply With Quote
Old 5th Nov 2020, 6:50 pm   #91
CrazySwede
Tetrode
 
CrazySwede's Avatar
 
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 61
Default Re: Trying to revive a Goodmans One Ten receiver

Trying out for the no1 spot in the setup together with the Garrard Zero 100 and Little Bear T10. Looking good in the cabinet! Still evaluating. Maybe the Swedish Sentec SP77 speakers are not the best match for it though....
Click image for larger version

Name:	IMG_20201105_182213.jpg
Views:	58
Size:	85.2 KB
ID:	219721
CrazySwede is offline   Reply With Quote
Old 6th Nov 2020, 8:42 am   #92
CrazySwede
Tetrode
 
CrazySwede's Avatar
 
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 61
Default Re: Trying to revive a Goodmans One Ten receiver

And today my dear wife inspected the One Ten in the cabinet. Passed immediate judgement:
"What a big, ugly thing! Change back to the other one at once!!!"

...so we have a bit of a domestic dispute to resolve here
CrazySwede is offline   Reply With Quote
Old 9th Nov 2020, 9:33 pm   #93
CrazySwede
Tetrode
 
CrazySwede's Avatar
 
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 61
Default Re: Trying to revive a Goodmans One Ten receiver

Hi!
Another thing to check I guess is the bias adjustment.
It's pretty well described in the service manual. But, I fel a bit stupid regarding where to connect the multimeter on the "supply rail". Grateful for bit of guidance with this
Click image for larger version

Name:	Screenshot_20201109_221835_com.google.android.apps.docs.jpg
Views:	27
Size:	73.8 KB
ID:	220037
CrazySwede is offline   Reply With Quote
Old 9th Nov 2020, 11:06 pm   #94
Richardgr
Pentode
 
Join Date: Oct 2019
Location: Tby, Sweden
Posts: 134
Default Re: Trying to revive a Goodmans One Ten receiver

Are we still talking about your other half’s unfounded bias against classic hifi?
Richardgr is offline   Reply With Quote
Old 9th Nov 2020, 11:08 pm   #95
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 16,778
Default Re: Trying to revive a Goodmans One Ten receiver

I can't read component designators or values on the schematic.

The written procedure talks about opening power supply connections (one at a time) to each amplifier and measuring the current. Because other things take current, it has you measure with the amplifier quiescent current fully backed off, and then adjusting it to an increase of 3mA

This procedure was written in the days when most workshops did not have meters that would go down to millivolts DC, but could measure milliamps.

HOWEVER, this procedure is risky because one small slip while power connections are broken can destroy some semiconductors in that power amplifier, and tracking down which is a major undertaking. Several people on here have destroyed amplifiers doing this. It's especially nasty if it's one you just fixed.

A more modern way relies on sensitive DC voltmeters. Most decent hand-held DVMs will dothe job.

Between the collectors of the two high power transistors is a pair of resistors in series.... low value ones. With the amplifier on, but no signal, measure voltage between the two collectors. It'll be small. Take care probing. As a double check, away from the amplifier, touch both probes together and see what reading error the meter gives you with zero volts input. On the schematic, read the values of those two resistors and add them. Use Ohms law with the voltage you measured (correcting for the zero volts reading makes it more accurate) and you have the amplifier's quiescent bias vurrent in the output stage.

Take care probing.... one slip is all it takes and it's kaput. But this way you don't have to disconnect wires and restore them.

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is online now   Reply With Quote
Old 10th Nov 2020, 5:19 am   #96
CrazySwede
Tetrode
 
CrazySwede's Avatar
 
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 61
Default Re: Trying to revive a Goodmans One Ten receiver

Thanks for good advice, David.
I have a decent digital multimeter so I will try the method you suggested. Will post some pictures first to check with you so I am using the correct connection points. Will probably be a couple of days.
Quote:
Originally Posted by Richardgr View Post
Are we still talking about your other halfs unfounded bias against classic hifi?
Hahaha, spot on !
CrazySwede is offline   Reply With Quote
Old 10th Nov 2020, 3:06 pm   #97
CrazySwede
Tetrode
 
CrazySwede's Avatar
 
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 61
Default Re: Trying to revive a Goodmans One Ten receiver

So, now I have been listening to the One Ten a bit more and find it to sound quite good but not as good as the JVC vr5535l that is my daily driver.

It sounds a bit more veiled/dull with less transparency and clearness than the JVC.

I dont know if its just its character of sound, a speaker mismatch or a case of ageing components. The only replacement I have done is the faulty transistor in the power supply and the two big reservoar caps (replaced with same specs).

Regarding the speakers I am using are seventies Swedish Sentec SP77:s that have two bass elements and two tweeters each. They are spec:ed (according to a leaflet I found online):
Power 50w
impedance 8 ohms
Sensitivity 4w

I also have a pair of Boston Acoustics A60:s that I may try. They are spec:ed:
Frequency Response: 55 Hz - 22,000 Hz 3 dB
Crossover Frequency: 6 dB/octave at 3000 Hz
Impedance: 8 Ω nominal, 6 Ω minimum
Sensitivity (at 1 watt/m input): 90 dB
Recommended Amplifier Power: 10 to 60 watts per channel

Are these a better match?

On the matter of recap, is this a path to explore and are there any specific capacitors exept for the reservoir (already replaced) I could start looking at? Unfortunately Im still a newbie regarding reading schematics and understanding the works of different components. But if I get some pointers on which component number to replace I can probably manage process of solder it right. The One Ten seems fortunately pretty easy to access for this kind of job.
But still, Id rather try to pinpoint a few caps than tearing them all out

Heres the service manual if anyone wants to take a peek:
https://drive.google.com/file/d/1yVeIvMhRFWPxUyPCpw28FlZgEhwAUIEf/view?usp=sharing


Thanks in advance for any wisdom regarding this!
CrazySwede is offline   Reply With Quote
Old 12th Nov 2020, 7:37 am   #98
CrazySwede
Tetrode
 
CrazySwede's Avatar
 
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 61
Default Re: Trying to revive a Goodmans One Ten receiver

So, Im pondering wether to start a recap work and begin with the rest of the power supply capacitors. They seem pretty easy an straightforward to replace. Good idea?

Click image for larger version

Name:	recap_psu1.jpg
Views:	12
Size:	81.7 KB
ID:	220162

Click image for larger version

Name:	recap_psu2.jpg
Views:	7
Size:	119.8 KB
ID:	220163
CrazySwede is offline   Reply With Quote
Old 12th Nov 2020, 8:37 am   #99
jjl
Heptode
 
jjl's Avatar
 
Join Date: Jan 2003
Location: Ware, Herts. UK.
Posts: 942
Default Re: Trying to revive a Goodmans One Ten receiver

With transistor equipment the general advice with regards to changing capacitors is that if it's working, leave it alone. There is no point in changing power supply capacitors unless you have excessive hum or another obvious fault.
This receiver does contain quite a few tantalum bead capacitors which can be unreliable, but you would be best advised to use the receiver and listen out for any unusual changes in its sound that may indicate a fault.

John
jjl is offline   Reply With Quote
Old 12th Nov 2020, 9:10 am   #100
CrazySwede
Tetrode
 
CrazySwede's Avatar
 
Join Date: Sep 2020
Location: Matfors, Sweden
Posts: 61
Default Re: Trying to revive a Goodmans One Ten receiver

Thanks for responding, John!
As I posted above theres no obvious fault in the sound like hum, static, pops etc. But I feel that the sound quality is a bit muffled / dull lacking som clearness. Bass can feel a bit boomy too.
Was thinking this could be caused by components ageing and going out of spec?
CrazySwede is offline   Reply With Quote
Reply

Thread Tools



All times are GMT. The time now is 7:20 am.


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 - 2021, vBulletin Solutions, Inc.
Copyright ©2002 - 2021, Paul Stenning.