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Old 11th Feb 2020, 9:35 pm   #128
DMcMahon
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Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,603
Default Re: Grundig TK 819 Any Useful Info

Spoke too soon, on a subsequent test the drive belt to the Supply table broke, so now no reverse play or RWD control with tape loaded. May be able to find a suitable belt by looking at some of my various spare belts.

With tape loaded, Play at 3 3/4 ips works and FFD works but when Stop pressed both spools are slow to stop and/or sometimes accelerate initially before stopping. Assume this may be a clutching tension issue, am not very confident either if the electrical clutch's are working correctly.

The biro tube mod added to the centrifugal push rod appears to be doing its stuff in terms of pushing up the contact plate when running at 7 1/2 ips, but have not yet tried operationally with the Relay C circuit connected because still do not have the GI contact electrically working.

Because the chassis is not in its case and therefore difficult to connect the loudspeaker, have not yet tested any sound playback, also removed the EL 84 output Pentode valve to protect the valve and output transformer with no load connected.

According to the schematic, there is a 5 ohm resistor dummy speaker load that can be switched in, but I have not yet worked out how to do it.
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