[Premium-Rx] Tuning problem with Racal R1772 / R1776 receiver

[Nico Dongen]

Hello all,

I recently purchased a Racal R1776 receiver what is the maritime version of the R1772 and it has a fault in the tuning. When I switch the Tuning Rate switch from fast to slow or vice versa the frequency jumps up or down. It is a random frequency change in the range from KHz to 100 KHz but mostly in the10Khz range. It happens most of the time but sometimes the effect disappears for a couple of minutes. Most of the time it will count up each time I switch the Tuning Rate till it reaches the end of the scale but I have seen it count down as well. 

I have another strange tuning effect
When I set the MHz switch for example to 3 MHz and with the tuning knob I tune down below 0 so it starts at 99999 again when it reaches 979.90  the 3MHz light goes off and the 2 and 4 MHz lights come on. The tuning then is locked until I switch the MHz switch to a different range. 

I don’t know if the two problems are related but I think it is a problem in the counter chain on the display board.

Any ideas on what could cause this kind of problems? 

Regards,  
Nico, Netherlands