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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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23rd Jun 2020, 8:39 pm | #1 |
Dekatron
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Location: Gateshead, Tyne and Wear, UK.
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Pye transistor portable PE12TBQ SW3 not working
A TV rental customer gave me this Pye radio set forty years ago. Got thinking it was about time I took a look at it. The set is a made for export Pye PE12TBQ, a four waveband all transistor portable radio receiver.
There might have been a version for the UK, 1138? The set has cleaned up nicely and works well on medium waves and two of the short wavebands. However, the set is dead on SW3 (15 to 22Mhz). The 'scope was connected to the emitter of the frequency changer transistor, V1 (OC171). This has proved that the oscillator is active on all wavebands except SW3. Note that the waveform on MW is not a pure sine wave, slightly better waveforms on SW2 and SW3. Switches check out OK so the prime suspect is the OC171. DFWB. |
23rd Jun 2020, 10:51 pm | #2 |
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Re: Pye transistor portable PE12TBQ SW3 not working
If you didn't have the scope, how else could you have sorted this problem? (If T1 is the problem)
Regards Poppydog |
24th Jun 2020, 12:46 am | #3 | |
Dekatron
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Re: Pye transistor portable PE12TBQ SW3 not working
Quote:
Tried different transistors but the fault persists. DFWB. |
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24th Jun 2020, 8:22 am | #4 |
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Re: Pye transistor portable PE12TBQ SW3 not working
Circuit for the PYE PE12TBQ is in the Radio Museum. https://www.radiomuseum.org/r/pye_pe12tbqpe_12_tb.html
V1 is listed as an AF115. It doesn't feel right advising you, but did you try an AF125? Mike Last edited by crackle; 24th Jun 2020 at 8:33 am. |
24th Jun 2020, 12:46 pm | #5 |
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Re: Pye transistor portable PE12TBQ SW3 not working
Hi Mike,
two HF transistors were tried, a Mullard AF114 and a TFK AF134, no improvement so the original OC170 has been refitted. The reason for the no SW3 fault has been found. The aerial coil L7 did not have a earth connection to the tuning capacitor. A wire link has now been soldered in between the coil and capacitor frame. Now the local oscillator is active on SW3 but there is still another fault to sort out. The tuning range is limited to the HF end of the waveband. On SW3 a 180pF capacitor C19 is inserted between the tuning capacitor and oscillator coil L8. it might be faulty. DFWB. |