View Single Post
Old 17th Feb 2020, 11:44 pm   #183
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,603
Default Re: Grundig TK 819 Any Useful Info

Repeated tape head demagnetiser hum test with tape loaded and running, same results as no tape loaded, i.e. loud hum from relevant PB head, e.g. right head for reverse playback.

Note - with/without tape the resultant hum is louder from the right hand head.

Did the same tests with the head connectors removed from the head assembly to see if could induce hum into the cables without the heads being connected, got zero hum, still get hum of course if head wiring touched at the pins of the connectors.

Probably stated it before but only get hum (during the hum induced tests) when Playback AND Track 1 (Forward Play) / Track 2 (Reverse Play) push buttons are selected, which is correct.

Tested EOT by momentarily (and longer when it did not work) grounding out the appropriate EOT sensor post, the right hand one worked reliably for RWD & Reverse Play, switching off the motor and drive and all tape transport push buttons reset with a loud clunk (ones that were selected).

The left hand EOT sensor post did not work at all, so another thing to add to list of things not working.
DMcMahon is offline