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Old 28th Nov 2021, 11:20 am   #1
DMcMahon
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Default Teleton F2000 AM/FM Receiver Check Out

Early 1970's nice looking wood cased receiver which I purchased recently through the Forum, sold as basically working, also purchased a second one which was sold as working but with low volume (will cover the second one in a different Thread).

Overall condition for its age pretty good, some wear to front panel lettering.

I remember Teleton from long ago and thought then that they had a Japanese connection, looking at some older Threads indicates Mitsubishi.

Powered up OK and AM/FM radio work but reception not good but still to try with an aerial connection.

Only tried headphones so far and some hum is noticeable on both channels, when I find some spare 2 pin DIN plugs I will check it on speakers.

Tested tape recorder input, works well on the left channel but nothing on the right channel. Strangely it works basically the same with the input selector switch at any of the 4 positions (with signal into the tape DIN) ?

More tests and investigations required to quantify further.

David
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Last edited by DMcMahon; 28th Nov 2021 at 11:27 am.
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Old 28th Nov 2021, 6:32 pm   #2
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Default Re: Teleton F2000 AM/FM Receiver Check Out

Found that on my 4 x phono to DIN signal lead I had mixed up an output with an input cable. With correct 2 phono cables connected at music source (CD player) now get both channels working OK (sounds good on headphones) and also correctly only now get the signal when switched to Tape.

The volume and balance controls are very touchy so need a good clean.

Using my finger as FM aerial get good FM radio reception but no stereo indicator.

Opened up and found one of the 4 scale illumination lamps blown so fitted new one.

Measured the DC supply at -26.6V with 500mV 10mS ripple, so looks good. Lamp supply measured 6.6VAC

David
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Old 2nd Dec 2021, 10:58 pm   #3
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Default Re: Teleton F2000 AM/FM Receiver Check Out

Wired up speaker cables with 2 pin DIN plugs and tested the receiver, sounds good with plenty of volume.

Measured the DC voltages and signal levels at the 4 output transistors for comparison data for the other F2000 with low volume.

As mentioned previously the rotary controls are noisy when adjusted, the volume control is really bad.

Removed the bottom wooden panel and the front panel expecting to get access to the controls for spraying in contact cleaner into the controls but disappointingly unable to see let alone clean the controls.

The volume, balance, bass and treble controls are fitted to the pre-amp PCB so the only way to access the controls is to remove the PCB which has turned into a mini nightmare.

After removing loads of wires and various bits and pieces I have got the pre- amp PCB about 3/4 out but it is fouling on both tuner boards which are held by a lots of tight wires. Still cannot get any contact cleaner in. Also just noticed that while struggling to remove the board the tuning cord has broken

Thinking that for the low volume F2000 that if the problem is not in the output transistors that the only way to fault find further would be to remove the pre amp PCB and using extension wires wire up the PCB to the unit wiring, but based upon how extremely difficult it is to extract the pre-amp PCB it may be a non starter.

David
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Old 3rd Dec 2021, 12:23 pm   #4
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Default Re: Teleton F2000 AM/FM Receiver Check Out

After a major struggle got the pre-amp board out and have sprayed the 4 controls with contact cleaner. Now need to refit everything and fingers crossed it still works and the controls are quieter.

Observation - All of the numerous green capacitors on the boards have a dirty rough (fine grit) covering (will not clean off), the same capacitors on my other F2000 are relatively clean and smooth.

David
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Old 3rd Dec 2021, 5:54 pm   #5
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Default Re: Teleton F2000 AM/FM Receiver Check Out

All re-assembled and still working (sigh of relief) plus the rotary controls are all now quiet in operation.

Outstanding job is to repair the tuning cord and restring, not looking forward to doing this, do not often do it and when I do always find it very difficult, could do with an idiots guide.

On of the dial bulbs blew so replaced it. The old lamps either have 2 or 3 vertical thick black lines on the face of the bulb or 2 or 3 horizontal thick black lines along the length of the bulb, the lines are roughly pen inked on.

Are these lines for dispersal of the strong light from the bulb ?

David
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Old 4th Dec 2021, 10:38 am   #6
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Default Re: Teleton F2000 AM/FM Receiver Check Out

Noted some differences from the schematic on this unit (my other F2000 does not have these differences) :-

1. The DC supply to the pre-amp board is taken from the -26V rail though a 220 Ohm resistor, dropping the voltage down to -23.2V

2. The DC supply to the larger Tuner board is taken from a point on the board (at -21.3V) that has the output transformers via a 1k Ohm, dropping the voltage down to -16.75V

3. There is a sizeable choke connected between the incoming mains live and the on/off switch.

All three above have definitely been added at some time, a little difficult to be 100% sure about the added resistors because the schematic does not show any component values.

David
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