Narrow-Bandwidth Television Association

Steve Anderson · Posted: Tue Feb 09, 2010 5:10 pm Post subject:

err...so how did you measure the voltage before? You presumably found the 0.02uF cap, one end is ground, the other is terminal 5. To that cap (somehow) the 470 Ohm resistor is connected. In that part of the circuit there are only two 2W resistors, this one and a 27k version. Simply look for a 470 Ohm 2W resistor, confirm visually or with a meter that one end is connected to the cap. Measure its resistance, and at the non-cap end measure the voltage.

Steve A.

smeezekitty · Posted: Wed Feb 10, 2010 8:24 am Post subject:

Steve Anderson · Posted: Wed Feb 10, 2010 11:26 am Post subject:

Modifications were/are done on a product so a change from 470 to 680 Ohms is nothing unusual. 720 Ohms is 6% high...fine...and you have to allow for the accuracy of your meter too, lesser ones are often 5% accurate on resistance, so there's nothing wrong with it. Yes the 2W ones are the largest in that area.

So, checked the raw supply as I requested above?

Steve A.

smeezekitty · Posted: Wed Feb 10, 2010 1:55 pm Post subject:

Steve Anderson · Posted: Wed Feb 10, 2010 2:06 pm Post subject:

Well I think the next course of action is to replace those two EHT rectifiers. And perhaps the 6CZ5. Sorry, but that's it.

FYI, datasheet for the 5642 attached.

Anyone else following this thread have any other suggestions?

Steve A.