I was self employed for 14 years reoairing tv's and videos and anything else that came my way,then came the Pace 4001 stuck in tune problem.
2 of these boxes with this problem still remain a mystery to me. The 1st is only used for spares now, the 12v rail was short and due to the complexity of the multi-layered board and the lack of a true circuit diagram I couldn't find the fault.
The second box when compared side by side to a working box is almost identical in voltages. The only difference I have found is a xoltage reading of 2.5v coming from the cim unit of the faulty box. This voltage disappears when the cim is removed and is obviously being generated in the cim as no other voltage readings to the cim are different.
I have a feellng that the 12C bus is at fault but have no way to prove this. My instinct is telling me that the cim, which I have substituted and the tuners are working but aren't talking to the processor.The nit isn't being recognised so tune is being displayed.
Would someone else with a stuck in tune 4001 try and see if they get the same 2.5v that I get. The far end of the cim from where the 12v input is there are 2 pins that are connected that give me this reading. Got to go now I have had 3 pints and need to sleep, has took me half an hour to write this post.
Regards........Chookey