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Originally Posted by yagosaga
I had trouble with wrong voltages and currents in the horizontal unit too. Read
http://audiokarma.org/forums/showthr...t=30364&page=5
and the following postings. I have renewed all the resistors on the horizontal oscilltor board. Some of these old resistors are crumbly. After renewing I got the correct values. But be careful with soldering. I had a short between grid and screen of the 6CB5 with fatal consequences.
Check R603 too. In my manual it has 150K, not 100K like in yours. In the set I found 90K and changed it with 150K.
BTW: Is A.G.C. ok? The first anode of the 6U8 should have -30 thru -70 volts. (Without signal input 0 volts). |
Say, thanks for pointing all of that out-- I had earlier been following your saga with the CTC-5 Aldrich with interest, but had forgotten that you too had troubles in the horiz osciallator section. I had a few "crumbly" resistors too, though the PC boards appear to be in good shape. Right now, I'm still waiting for some new caps to arrive that I ordered, but should have them in a few days. [BTW, yes, I know that C606 should not be replaced with a ceramic; I only did that as a test to confirm that it would indeed raise the oscillator frequency. Ceramic caps are not stable enough for this sort of timing application...]
Since old_tv_nut posted the schematic for the CTC-5A (through 5H) chassis version (the "Special"/"Super" models), I may as well fill in with the scematic for the CTC-5N (through 5AB) chassis version (the "Deluxe" models) as found in my edition of the RCA manual. Note that the tuner schematic is not included in this diagram.