Quote:
Originally Posted by vortalexfan
I found a box of 47k Ohm 1W 2% tolerance Flameproof resistors that are branded RCA, a package with a 56K Ohm 1W 2% Flameproof Resistor that is Branded Sylvania and I have a package of 56k Ohm 1/2W Carbon Film Resistors that I had left over from when I was restoring my Meck TV last year that either one of those I think should work in this unit.
I think I could just solder it under the chassis between the two points where the resistor holder above ties into the circuit and then just leave the old fuse style resistor in the holder above the chassis for appearances sake (I cleaned up the glass housing of the old resistor and I looked inside and it looked like there wasn't anything in there anymore which might explain why it measured open).
Does any of these resistors I mentioned stick out as far as one that might work better than the other in this position?
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Really any of them should be fine. According to the voltage/current chart that resistor will be dropping around 45v, so 45v x 2ma is a whopping 90mw of dissipation.
Quote:
Originally Posted by vortalexfan
Also I found a couple of capacitors in my capacitor stash that might work in place of the old filter caps in the filter supply circuit, one is a 4.7 MFD 250 WVDC Electrolytic and the other is a 2.2 MFD 100 WVDC Electrolytic.
Would those work fine in the filter cap positions on this radio seeing as they didn't specify a Working Voltage for the original filter caps?
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Assuming B+ at the second filter around 175v, I would use 4.7 mfd @ 250wvdc for 102 and 103. That'll give you some good headroom and a little extra filtering. For that matter you could use a couple 10mfd.
Quote:
Originally Posted by vortalexfan
Also the 5,000 Ohm "B" Resistor in this radio's Power Supply/Audio Circuit measures open as well, and I was wondering what kind of wattage of resistor it is, its rather large and looks like it might be a 5 or 10 Watt WW Power Resistor but I'm not sure as it doesn't have any information written on it.
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175v - 90v = 85v across the 5k.
85v/5000 = 17ma.
85v x 17ma = 1.45watts. So a 5 watt should be very conservative.
Everything is ballpark based on the values listed in the Bosch model 28 voltage/current chart and schematic.