The following is posted exactly as found in a text file on an old floppy
disk (from early 90's). I hope it's of some interest/use.

Regards,
Andrew B
(24th Feb 2007)



From: G3YRH@GB7MSF.#18.GBR.EU
To  : PMR@GBR

The following are common faults on the 5000 series of equipment.
Power connector if you are using the original power cables
and connectors, the common fault is poor connection on the crimped 
leads, i suggest soldering.
RX but no TX internal connector near back of chaasis this supplies
permanent 13.8v to pa transistor corrosion of pins.
Tx but no RX 1 ohm resistor in series with audio amp it is located between 
the on/of and squelch defeat switch,at same time upgrade ua2002 audio chip
to a ua2003 if not already done.
Constant squelch locate large black inductor behind volume control maybe 
open circuit, or ingress of damp along the front of the pa shield you can see this by its white deposit.

INT TX
PA transistor or driver leads not soldered i.e dry joint requires heavy 
duty iron, filter components dry joint. On the UHF version be careful 
if you replace the pa as the driver transistor has a washer between 
the board and chassis fatal if not replaced loss of driver transistor.
UHF version poor sensitivity , remove rf board and very carefully
remove the screen from the Rx front end by removing screws on underside.
clean the casing of the filter as with constant adjustment filings from 
the threads collect in the casing. causing loss of gain.

Synth Version
if you have a problem with feedback when the volume is increased 
check the vco coils and see if they have been cut down to the level 
of the turns. if not cut off surplus.
Lock problems change the lock amp transistor with a vmos fet and replace
the origanal base resistor 47k with 82k also replace the 1uf tant with 
a 2.2n this stops pulses on the lock det line.

g3yrh@gb7msf