Quad FM4 problems - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Mikeymoo · 30th Oct 2019, 2:40 pm

Hello, just my 2nd time here but still haven't been able to get the above tuner working. Have checked the small fuse which is ok. Have changed the Rifa cap that was bulging and now have a feeling that the transformer might be the problem. Have finally obtained an analogue meter and from my basic search can advise that there is power up to the transformer. Being a complete novice I'm not too sure about the next step so hopefully someone can advise in plain language. Many thanks.

Station X · 2nd Nov 2019, 11:16 am

I have no experience of Quad FM4's, so can only give you general advice.

Check that the unit's voltage selector is set correctly.

Carry out the test described in post #14.

If all is OK you're going to have to power up the unit and check the voltages from the power supply.

I've attached an extract from the circuit showing the PSU. If you can't identify the various components, post some pictures of the unit's interior.

Mikeymoo · 2nd Nov 2019, 5:00 pm

Graham, thanks for getting back to me. I have removed the transformer and can see that it's burnt out on the primary circuits. So now I'm trying to ascertain the specification of the transformer so that I can purchase it here hopefully but having difficulty finding this information. Do you have any tips? Regards Mikeymoo

alanworland · 2nd Nov 2019, 5:11 pm

Worth an email to Quad - I've found them very helpful. Quote serial number of tuner.

Alan

nutteronthebus · 2nd Nov 2019, 7:15 pm

The other thing is the mains switch as it is a dual pole ( turns both +ve and -VE off ) as these are known fault the TX may be ok

Dave

Mikeymoo · 3rd Nov 2019, 2:29 am

Dave, what's the TX?

Kentode · 3rd Nov 2019, 8:16 am

TX is shorthand for Transformer. Can you post a picture of this so we can see its condition?

Hope this helps.

Station X · 3rd Nov 2019, 10:53 am

Looking at pictures on the web it appears that the mains transformer is of the split bobbin type, so rewinding just the primary might be comparatively easy if it is indeed faulty.

A few simple resistance and voltage checks would soon show whether the transformer is faulty or not, assuming it's not been roasted to a cinder.

Mikeymoo · 3rd Nov 2019, 11:46 am

Here is a foto of the transformer. Secondary windings ok.

Station X · 3rd Nov 2019, 11:52 am

That's definitely had it. A phone call to Quad or a PM to Ed Dinning is in order.

Bear in mind that the winding will have burnt out for a reason. There may be further faults in the PSU area.

Mikeymoo · 3rd Nov 2019, 12:26 pm

I have changed the Rifa snubber that was bulging and also had a crack in it. This component appears to be problematic according to others who have had issues with the tuner. However the transformer was burnt out before I substituted the Rifa. Could this have caused the transformer to burn out?

Station X · 3rd Nov 2019, 1:01 pm

I wouldn't like to say. The Rifa snubber is connected directly across the mains, so if it failed short-circuit I'd expect it to blow the mains fuse rather than blow the fuse in the tuner or burn out the mains transformer.

I had a snubber explode in a Cambridge amp. All it did was blow the fuse in the mains plug. There was no other damage.

Mikeymoo · 3rd Nov 2019, 1:21 pm

Graham, thanks for the advice. I've seen a site based in Belgium that has the transformer but at €64.00 I didn't really want to take a punt and burn out the transformer. I have sent an email to Quad so hopefully they might be able to advise. Cheers

Mikeymoo · 3rd Nov 2019, 3:57 pm

Quote:

Originally Posted by Station X

That's definitely had it. A phone call to Quad or a PM to Ed Dinning is in order.

Graham, does Ed Dinning work for Quad or were you meaning a PM personal message? To Ed on this forum? Thanks

Station X · 3rd Nov 2019, 4:00 pm

Ed Dinning is a forum member who rewinds transformers. He does not work for Quad.

You need to carefully consider the economics of any repair.

Ted Kendall · 3rd Nov 2019, 8:32 pm

I had an FM4 transformer fail after long service. The replacement has been in the unit for over a decade, so I think current stock is OK!

evingar · 3rd Nov 2019, 8:40 pm

Quote:

Originally Posted by Station X

Ed Dinning is a forum member who rewinds transformers. He does not work for Quad.

You need to carefully consider the economics of any repair.

They seem to be going for about £150 on eBay.
I was keen to get one a while back to fit with my Quad power and pre amp of that era. I know it's tantamount to heresy to say so in here but things have moved on and getting a DAB / Internet tuner seems to be the way forward now.

Radio Wrangler · 3rd Nov 2019, 8:46 pm

One thing to be cautious about if you are attracted by a DAB/streamer sort of tuner. If they also claim to receive stereo FM, expect that function to be essentially un-listenable. They are often just features added to pad out the marketing blurb and compete with others of that ilk. The manufacturer certainly does not intend to spend any money on that feature.

If you still want off-air radio, you may want to hang on to that Quad, and if you have decent gear with it, you may well DAB not exactly competitive.

David

Ted Kendall · 3rd Nov 2019, 10:24 pm

FM multiplex has a bandwidth of 15kHz, s/n ratio of up to 70dB and typically under 1% peak distortion. Granted, just about everybody uses maladjusted Optimods, but R3 is quite subtle. DAB starts by throwing away large amounts of information, but we are repeatedly told that it is digital and therefore better - b

s.

Mikeymoo · 4th Nov 2019, 3:02 am

Interesting comments about going down the DAB route. They don't have DAB here in Portugal but yes with all the grief that the Quad has given me I feel slightly tempted to ditch it and maybe get an internet tuner. It's all well and good that the FM 4 is a quality sounding tuner but if it doesn't function it's all rather redundant really.

30th Oct 2019, 2:40 pm	#21
Mikeymoo Retired Dormant Member Join Date: May 2015 Location: Porto, Portugal Posts: 17	Quad FM 4 not working. Hello, just my 2nd time here but still haven't been able to get the above tuner working. Have checked the small fuse which is ok. Have changed the Rifa cap that was bulging and now have a feeling that the transformer might be the problem. Have finally obtained an analogue meter and from my basic search can advise that there is power up to the transformer. Being a complete novice I'm not too sure about the next step so hopefully someone can advise in plain language. Many thanks.

2nd Nov 2019, 11:16 am	#22
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Quad FM4 problems I have no experience of Quad FM4's, so can only give you general advice. Check that the unit's voltage selector is set correctly. Carry out the test described in post #14. If all is OK you're going to have to power up the unit and check the voltages from the power supply. I've attached an extract from the circuit showing the PSU. If you can't identify the various components, post some pictures of the unit's interior. Attached Thumbnails __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

2nd Nov 2019, 5:00 pm	#23
Mikeymoo Retired Dormant Member Join Date: May 2015 Location: Porto, Portugal Posts: 17	Re: Quad FM4 problems Graham, thanks for getting back to me. I have removed the transformer and can see that it's burnt out on the primary circuits. So now I'm trying to ascertain the specification of the transformer so that I can purchase it here hopefully but having difficulty finding this information. Do you have any tips? Regards Mikeymoo

2nd Nov 2019, 5:11 pm	#24
alanworland Heptode Join Date: Feb 2011 Location: Southend, Essex, UK. Posts: 803	Re: Quad FM4 problems Worth an email to Quad - I've found them very helpful. Quote serial number of tuner. Alan

2nd Nov 2019, 7:15 pm	#25
nutteronthebus Hexode Join Date: Jun 2011 Location: Glossop, Derbyshire, UK. Posts: 487	Re: Quad FM4 problems The other thing is the mains switch as it is a dual pole ( turns both +ve and -VE off ) as these are known fault the TX may be ok Dave __________________ Any tool can be used as a hammer but a screwdriver makes the best chisel

3rd Nov 2019, 2:29 am	#26
Mikeymoo Retired Dormant Member Join Date: May 2015 Location: Porto, Portugal Posts: 17	Re: Quad FM4 problems Dave, what's the TX?

3rd Nov 2019, 8:16 am	#27
Kentode Octode Join Date: Mar 2015 Location: Yorkshire, England. Posts: 1,303	Re: Quad FM4 problems TX is shorthand for Transformer. Can you post a picture of this so we can see its condition? Hope this helps. __________________ Regards, Ken. BVWS member

3rd Nov 2019, 10:53 am	#28
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Quad FM4 problems Looking at pictures on the web it appears that the mains transformer is of the split bobbin type, so rewinding just the primary might be comparatively easy if it is indeed faulty. A few simple resistance and voltage checks would soon show whether the transformer is faulty or not, assuming it's not been roasted to a cinder. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

3rd Nov 2019, 11:46 am	#29
Mikeymoo Retired Dormant Member Join Date: May 2015 Location: Porto, Portugal Posts: 17	Re: Quad FM4 problems Here is a foto of the transformer. Secondary windings ok. Attached Thumbnails

3rd Nov 2019, 11:52 am	#30
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Quad FM4 problems That's definitely had it. A phone call to Quad or a PM to Ed Dinning is in order. Bear in mind that the winding will have burnt out for a reason. There may be further faults in the PSU area. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

3rd Nov 2019, 12:26 pm	#31
Mikeymoo Retired Dormant Member Join Date: May 2015 Location: Porto, Portugal Posts: 17	Re: Quad FM4 problems I have changed the Rifa snubber that was bulging and also had a crack in it. This component appears to be problematic according to others who have had issues with the tuner. However the transformer was burnt out before I substituted the Rifa. Could this have caused the transformer to burn out?

3rd Nov 2019, 1:01 pm	#32
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Quad FM4 problems I wouldn't like to say. The Rifa snubber is connected directly across the mains, so if it failed short-circuit I'd expect it to blow the mains fuse rather than blow the fuse in the tuner or burn out the mains transformer. I had a snubber explode in a Cambridge amp. All it did was blow the fuse in the mains plug. There was no other damage. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

3rd Nov 2019, 1:21 pm	#33
Mikeymoo Retired Dormant Member Join Date: May 2015 Location: Porto, Portugal Posts: 17	Re: Quad FM4 problems Graham, thanks for the advice. I've seen a site based in Belgium that has the transformer but at €64.00 I didn't really want to take a punt and burn out the transformer. I have sent an email to Quad so hopefully they might be able to advise. Cheers

3rd Nov 2019, 4:00 pm	#35
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Quad FM4 problems Ed Dinning is a forum member who rewinds transformers. He does not work for Quad. You need to carefully consider the economics of any repair. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

3rd Nov 2019, 8:32 pm	#36
Ted Kendall Dekatron Join Date: Jul 2008 Location: Kington, Herefordshire, UK. Posts: 3,675	Re: Quad FM4 problems I had an FM4 transformer fail after long service. The replacement has been in the unit for over a decade, so I think current stock is OK!

3rd Nov 2019, 8:46 pm	#38
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,902	Re: Quad FM4 problems One thing to be cautious about if you are attracted by a DAB/streamer sort of tuner. If they also claim to receive stereo FM, expect that function to be essentially un-listenable. They are often just features added to pad out the marketing blurb and compete with others of that ilk. The manufacturer certainly does not intend to spend any money on that feature. If you still want off-air radio, you may want to hang on to that Quad, and if you have decent gear with it, you may well DAB not exactly competitive. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

3rd Nov 2019, 10:24 pm	#39
Ted Kendall Dekatron Join Date: Jul 2008 Location: Kington, Herefordshire, UK. Posts: 3,675	Re: Quad FM4 problems FM multiplex has a bandwidth of 15kHz, s/n ratio of up to 70dB and typically under 1% peak distortion. Granted, just about everybody uses maladjusted Optimods, but R3 is quite subtle. DAB starts by throwing away large amounts of information, but we are repeatedly told that it is digital and therefore better - bs.

4th Nov 2019, 3:02 am	#40
Mikeymoo Retired Dormant Member Join Date: May 2015 Location: Porto, Portugal Posts: 17	Re: Quad FM4 problems Interesting comments about going down the DAB route. They don't have DAB here in Portugal but yes with all the grief that the Quad has given me I feel slightly tempted to ditch it and maybe get an internet tuner. It's all well and good that the FM 4 is a quality sounding tuner but if it doesn't function it's all rather redundant really.