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Old 21st Feb 2020, 7:25 pm   #186
DMcMahon
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Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Grundig TK 819 Any Useful Info

Tried checking continuity again from the PB heads to the input of the EF804 Valve (AKA EF86) at C1 capacitor but no joy. With tape playing scope probed C1 and also for good measure the anode output of the valve at C4 but no signal seen.

Also scope probed the heads wiring at the connectors on the heads assembly but nothing seen with tape playing.

Its looking more and more like there is no signal from the PB heads. Will wait until my spare PB/Record head arrives and fit that and try again.

Noticed that the EF804 anode DC voltage seemed high at 200 volts, schematic valve base info indicates 50 volts, this possibly may indicate the valve is not conducting.
Will look at this further once I get a signal at the control grid (C1 input).
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