View Full Version : I need help, Cant find a Schematic

02-23-2005, 07:20 PM
Me and my buddy have been working on my grandpa's 82 Curtis Mathes Console TV and we cant get the Digital tuner to work. We have channel 2 and 3, but the picture is crap on the TV (3 has no color and lines in the pic while 2 has color, but is snowy). All the other channels are snow. My friend thinks its in the AGP circuit? He says its pointless to go probe around without something to help to look for the problems.

Anyway The TV set Model # is H2525RP
the Chassie is a C84-3

It appears NEC made the chassie in this.

I hate to throw away this set. Lotta memories with this TV. Anyone got a SAMs on this or where I could get one?

Thank you

02-25-2005, 10:39 AM
Although I can't say for sure what the issue would be having never seen this particular model, my first stab at it would be to check for dry solder joints and perhaps the electrolytic capacitors next. It's definately a stability problem in the tuner. The higher in frequency it goes, the less stable it gets. This can also be caused by contacts on any plug-in components/boards that get dirty. Is it one of those 12-preset tuners that CM loved so much in the late 70's/early 80's or is it a 10-key calculator-type channel entry? If it's the 12-preset variety, check the varactor knobs on each channel (behind a hidden door). Just like the early VCRs, you have to twiddle the knobs for each and every channel....I was so happy to see that technology die!


02-25-2005, 07:00 PM

Its an all digital tuner. It has a 2 digit digital readout on the front of it and and a basic channel Up and Down buttons on it. My grandpa seems to recall buying this TV because it was one of CM's very first all digital tuner. He didnt want to deal with the preset TV's because of cable.

02-26-2005, 11:29 PM
bad grounds in the tuner(square can)
anything that causes loss of /noise on the +33 tuning voltage source.
can cause all sorts of gremnlins like aft hunting,the tuner rolling around /drifting wildly,ect
you have a rebadged nec.

02-26-2005, 11:41 PM
nec... YUCK!!!
NEVER run into thier projection sets. absolute trash.

if i had to choose between zenith and nec with the run of tubes, id choose zenith.