TEAC 80-8 solenoid engagement issues

[Jasper G]

Dear reel to reel wizards, I'm currently waking a stored 80-8 and need some advice...

I have problems with the takeup reel brake solenoid and the capstan solenoid. Both work every now and then, but if at all, it is after a longer power-off period. Their power (if they started working in the first place) seems to diminish after some operating time. Judging from the worn-out takeup reel motor brake (my fresh felt refurbishment already worked out ) this problem has probably been around for some time and gone unnoticed by the previous user.

I'm by no means an electrical engineer but with the service manual and some investigation I found out the following:

All fuses are ok, power supply voltages are ok on the service test points (also under load, 29V/5,1V/24V respectively), solenoid pistons seem clean and move freely, voltages over the two solenoid contacts (with the resistor in place) measure just over 8V for both brakes when released - spike of 24V dropping to 14V for the capstan solenoid upon playback...

Any help would be greatly appreciated! Getting a pro tech to look at it shouldn't be a problem but I rather fix and learn as much as possible myself... Thanks for reading!

 

[Michael Doncaster]

It could be, that the grease used to lubricate the mechanism has dried out causing the moving parts to bind.

The grease would need to be cleaned off, and replaced with Lubriplate 105 white lithium grease.

 

[Jasper G]

Thanks Michael, I remember the moving parts being very clean, but I guess the insides could still be sticky; I'll have to check...

 

[Michael Doncaster]

I should also mention, that the solenoids should be perfectly clean and totally free of grease. Otherwise they will gather dust and debris, and that would make them sluggish and stop working.