Just recently acquired a MK4 TV and a load of service data manuals for the MK.12A, MK,12W, MK.1 and MK.3
Sods law nothing for the MK.4
My mark 4 set is dead I had it powered up with a nice bright raster and was trying unsuccessfully to tune in a Test Card. I powered down and went to make a brew, when I came back and tried to power on the set again, this time it was totally dead. Therefore was wondering if anyone has a scan of the service manual they can upload for me. I suspect there are protection circuits in operation but never having seen a MK4 until today, I've no idea where or what to look at without data.
CrustyTV Television Shop: Take a virtual tour
Crusty's TV/VCR Collection: View my collection
Crustys Youtube Channel: My stuff
Crusty's 70s Lounge: Take a peek
Sorry I no longer have the diagram, we never had a full manual either just a circuit diagram, I think it might have been restricted to dealers only (Malc might have one) .
There is a good servicing article in the TV mags though, Jan 1994, which was arguably more useful than just the diagram we had.
I just found the 1982 one by Stephen Clay and uploaded it to the service section here I'll have a look for the 94 one as I have some 90's television mags.
CrustyTV Television Shop: Take a virtual tour
Crusty's TV/VCR Collection: View my collection
Crustys Youtube Channel: My stuff
Crusty's 70s Lounge: Take a peek
Just found and added the 1994 article by Chris Watton. Thanks for the heads up on that article ?
access via top menu "Service" | "Colour TV" | "Servicing The Sets"
Lots of good tips for the fault condition I have before me ?
CrustyTV Television Shop: Take a virtual tour
Crusty's TV/VCR Collection: View my collection
Crustys Youtube Channel: My stuff
Crusty's 70s Lounge: Take a peek
I've got a manual pack for the Mk IV, they are quite simple circuits, a TDA1060 SMPSU, so take care when taking measurements. I remember sorting out most dead set issues with a meter and 60W lamp. Things to look out for are poor contacts with the pressac connectors and green ribbon cables and dry joints on all panels but especially on the scan panel, where there may be burn up too. 90° and 110° scan panels are identical but with component changes.
For a dead set
Most likely to be poor joints .Make sure that the light blue oblong cap next to the BU326 chopper transistor is properly soldered before applying power as a bad joint on this will damage the chopper making it open circuit and blow the faces off a few transistors and burn a lot of transistors in the process
Well they say ignorance is bliss, oblivious to those facts and prior to making the request for data in this post, power was applied, thankfully no drama. This in no small part due to it being a later model where the failings described had been addressed by Rediffusion. What did turn out to be the cause was the PSU Thyristor THY1, a 2P5M.
All detailed here
data added here
and here
?
p.s.
If anyone fancies a MK4 then Stan has a nice 26" looking for a home and it has the RCA tube, I was tempted by that too
CrustyTV Television Shop: Take a virtual tour
Crusty's TV/VCR Collection: View my collection
Crustys Youtube Channel: My stuff
Crusty's 70s Lounge: Take a peek
