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Fons cq-30 repair help.

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Fons cq-30 repair help.

Postby BlackD007 » 30 May 2017 07:50

Hi. I have problem with my fons cq-30. Sometimes it stop working at all. Any speed not functional, platter don't spin.But if my fons stay some hours it magically start working like nothing happens.Thanks for help.Sorry for my english.
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Re: Fons cq-30 repair help.

Postby Alec124c41 » 30 May 2017 23:34

You could use come contact cleaner, to clean all the switches and controls, inside them. This might clear up your problems.

Cheers,
Alec
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Re: Fons cq-30 repair help.

Postby nat » 30 May 2017 23:44

The Fons has some fairly complicated (by turntable standards) electronics. Additionally the speed potentiometers are fairly fragile and long, and they can be funky -- I had all sorts of starts and stops until I figured out that the 33 pot wasn't working properly (I suspect that the resistance wire was broken in place and made contact now and again, but not always). Frustrating when you can't relay on a table.
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Re: Fons cq-30 repair help.

Postby Joe » 20 Jun 2017 20:24

I am looking for an SME armboard for a FONS International Mk 1 - I have someone that will make one for me, but I need a template - does anyone know of a template or has an armboard they can trace, photograph and scan?
Many thanks
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Re: Fons cq-30 repair help.

Postby Chiltern » 23 Jun 2017 18:08

There is a schematic in the library (under International), the circuit will be basically the same for a CQ30.

The switch bank, speed controls and the servo motor can all give trouble. The speed controls can be repaired, but great care is required, they are brittle now. The resistance track is much like that in a volume control but a simple flat track, however it was rivetted in place originally, over time the connection between the rivets and the track loosens and the circuit is lost.

The motor can be replaced by a Philips item and a thread here has in the past detailed this.

Best to research all of the Fons threads on this forum.

Good luck

Alan
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Re: Fons cq-30 repair help.

Postby bradc944 » 19 Oct 2017 00:43

I just got 'the call' from my audio tech... the motor in my CQ30 has shorted out. So, gonna look for the Philips replacement thread.

Here's a hint: if the motor shorts out, it may take one of the transistors with it... so BE CAREFUL, don't know if there are equivalents available on this side of the Atlantic for the UK transistors.

Brad
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Re: Fons cq-30 repair help.

Postby bradc944 » 19 Oct 2017 21:20

Just got the CQ30 back and on my bench. Pulled out the bad (and I DO MEAN BAD) motor... shorted because brushes/bushings were all rattle rattle inside the case. The transistor that can and will go PEWF is VT4 (the BC338), so have replacements handy if your motor is suspect. BTW, anyone have the US equivalent part numbers for the transistors noted on the wonderful HAmish schematic?? Thanks in advance for those...

The Philips 212 replacement motor is on its' way here, looks like a simple drop-in... I *do* assume that the 2 black tacho leads are separated out like on the Fons motor harness? Anyone that has done the Philips motor swap, please advise... thanks.

Will post some photos of the gallery as the replacement progresses. THANK THE GODS FOR ALL YOU FONS OWNERS OUT THERE!!! Looking forward to having my Baby Precious back running!

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Re: Fons cq-30 repair help.

Postby bradc944 » 19 Nov 2017 03:14

Well...... the Philips motor is in, things are wired up, and strange things are happening. I have some voltages that are strange, such as 22v going to the motor, instead of the 13v that should be there. The motor starts out fine, then goes into what best would be called 'runaway mode'. The voltage will drop if there is a load, but then ramps back up to 22v.

My question: should I be replacing the 4 diodes in the power input section (the larger ones), or is the tacho circuit on the motor not registering properly... I'm going to put the output from the 4 diodes that make the larger bridge rectifier on to a scope to see if there is any 'dirtiness' (ripple, or other waveform that shouldn't be there) present... if there is, then the diodes will be replaced, and going from there.

I trust nobody else has had this issue when using a Philips 212 motor as a replacement... maybe I should get another one in case the tacho pulse output is wonky...

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Re: Fons cq-30 repair help.

Postby HAMISH119 » 19 Nov 2017 16:48

bradc944 wrote:The Philips 212 replacement motor is on its' way here, looks like a simple drop-in... I *do* assume that the 2 black tacho leads are separated out like on the Fons motor harness?

bradc944 wrote:Well...... the Philips motor is in, things are wired up, and strange things are happening. I have some voltages that are strange, such as 22v going to the motor, instead of the 13v that should be there. The motor starts out fine, then goes into what best would be called 'runaway mode'. The voltage will drop if there is a load, but then ramps back up to 22v.

I trust nobody else has had this issue when using a Philips 212 motor as a replacement... maybe I should get another one in case the tacho pulse output is wonky...


See Rolv-Karsten's post regarding the Philips GA212 motor incompatibility.
The GA212 Tacho Control circuit differs substantially from the FONS and other Philips models. :shock:

The motors from Philips GA222, GA312 & GA406 should be 100% compatible. :idea:

Good Luck!
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