Quad FM 4 not working.

[Mikeymoo]

Hello, wondering if anyone out there could advise me on how to get the tuner up and running. I've got a QUAD FM 4 tuner that is not powering up. Have checked the fuse which is ok and have replaced the Rifa cap that was bulging. Have power up to the transformer so not the on/off button. I've got an analogue meter and very keen to try to sort problem(s) myself but just need some guidance if possible. Regards

 

[rayma]

Check the power supply voltages, starting with the transformer secondary AC voltages.
Quad FM4 - Manual - FM Stereo Tuner - HiFi Engine

 

[Mikeymoo]

Rayma, thanks for getting back to me. No readings on the 3 secondary one's and only a very low voltage on 1 of the primary. There are 2 primary one's. Apologies re. my wording but will add I'm very much in the novice camp. Cheers Mikeymoo

 

[rayma]

Rayma, thanks for getting back to me. No readings on the 3 secondary one's
and only a very low voltage on 1 of the primary. There are 2 primary one's.

If the meter is on ACV, then the transformer is probably open circuit.
Do some more checking on it, right on the ends of the windings.
Are they soldered, or in a connector?

 

[Mikeymoo]

Ok. Did some more checking at the end of the windings and still no voltages except the very low one. Used an analogue meter on ACV. So I'm presuming that it isn't a dry joint as checked on the pcb and also the end winding coming out from the transformer. They are soldered onto the pcb. So what now? Do you suggest that I desolder the transformer and check visually? I think this is the 2nd transformer as had it serviced a few years ago and they replaced the original. Thanks for the help.

 

[rayma]

Transformers can have an internal fuse that blows, rendering the transformer useless.
Looks like it's time for another one. There could be other problems as well, though.

 

[Mikeymoo]

It's a smallish transformer so I doubt that it has a fuse. There is a fuse just under where the socket is. This fuse is good as that was the initial problem. So progress of sorts?!? What might be the 'other problems'? I've seen a site in Belgium that has the transformer but at €64.00 I didn't really want to take a punt and blow or short it out. Was hoping that I could find the equivalent transformer here in Portugal but don't know what it's rates at. What else do you think that I should do? Cheers

 

[rayma]

If you remove the transformer and ohm the windings, you'll find one is open (probably the primary).
Smaller transformers are the ones often having internal fuses. A complex unit like this could have
various other problems as well.

 

[Mikeymoo]

Right, so take the transformer out, check if it has a fuse. If not, then put the meter on it to get the resistance (Ohms). Can I do this before removing it? Will the ohms give me a guide should I purchase a new transformer or is it not that simple? It's on 240 volts but there's 2 primary's and 3 secondary's. So does this make it difficult to get the equivalent one? Thank you for your patience.

 

[rayma]

I can only recommend that a qualified technician do the actual repair.

To check the transformer primary, you can measure the continuity of the primary in circuit,
with the AC line unplugged and the power switch on.

 

[Mikeymoo]

When you say AC line unplugged & the power switch on, do you mean not plugged into the mains but put the on/off switch as if in the on position?

 

[rayma]

When you say AC line unplugged & the power switch on, do you mean
not plugged into the mains but put the on/off switch as if in the on position?

Yes, of course. However I do not recommend going any further at this time,
as some basic knowledge is necessary to be safe.

 

[Mikeymoo]

Ok, there is no reading on the primary circuits but there is on all of the secondary circuits. 5 ohms on 2 of them and 125 ohms on the other. Where does that leave me? Still with a dud transformer?

 

[rayma]

Ok, there is no reading on the primary circuits but there is on all of the secondary circuits. 5 ohms on 2 of them and 125 ohms on the other. Where does that leave me? Still with a dud transformer?

Definitely, take it to a technician. This works on 240VAC, deadly stuff.

 

[Mikeymoo]

Rayma, I've just removed the transformer and can see that it's burnt out hence tuner not powering up. I will try and source a new one here and replace it and hopefully hey presto it's all go. Trouble is I haven't been able to find out exactly what the values are of it. Tried looking for it on the net but haven't had much luck. Any idea's where I might get some info?

 

[rayma]

Rayma, I've just removed the transformer and can see that it's burnt out hence tuner not powering up. I will try and source a new one here and replace it and hopefully hey presto it's all go. Trouble is I haven't been able to find out exactly what the values are of it. Tried looking for it on the net but haven't had much luck. Any idea's where I might get some info?

Quad. Again, this is beyond what you should be doing. Very dangerous.

 

[PRR]

Listen to Rayma. Aside from the considerable risk of working with 230V mains power, I can estimate some of the specs, but not enough, and I have never seen a commodity transformer much like this. I could cobble it up out of 2 or 3 transformers but it would not fit the case. This had to be a custom part. You will get it from Quad, or a Quad specialist, or not at all. If that does not work out, _I_ would put it to auction as "Not working, for parts only". There is some market for such items.

 

[Drewaudio]

My FM4 transformer failed. I contacted Quad and they shipped a replacement out. Talk to Quad.

 

[Mikeymoo]

How much did it cost including postage etc? This will be the 3rd one and I'm reluctant to spend a small fortune on it but also want to get it up and running obviously. Cheers

 

[Drewaudio]

Mikeymoo, it was a couple of years ago so I can't remember the cost. I'm in New Zealand so freight was a killer. Quad told me that they redesigned the transformer because the original design can short between turns in the winding and overheat....that's what my one did. The new one is perfect.