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In general, the same reason to do it in audio would apply to a scope also. You might as well (there's no 'cost' to doing it, right?). Pete

Sometimes the plates are bent during initial calibration to linearize the? scale or hit calibration points within the range. Some people "straighten them out" because "someone" had to bend things out

There’s really no reason to check the capacitance of the frequency tuning capacitors. If some of the plates are significantly bent (but are not touching), the oscillator will still work but will be

OK, thanks They look clear of debris. Is there a way to check their capacitance or resistance easily ? I have an LCR meter. Regards

Oh, I agree that relative permittivity is probably a better term, and it is even possible that I will get used to it in the 20 or 25 years I may have left in this life.? I did, after all, get used to

Be sure to carefully check the frequency tuning variable capacitors for any contaminants causing plate to plate short circuits, which will stop any oscillation in any band.

That's good news about R40 and also indicates no shorts in the transformers! That still leaves you with no current draw. The DC voltage to the 6CW5s is applied through R27 & 28 which each drop 30

The cathodes (pin 3) of the 6CW5's measure 12K to chassis.

R40 measures at 10k.

?? FWIW, 122 Megohms makes it a 410-B.? Probably makes no difference if a lower resistance is used.

Thanks Morris. Sorry in my haste late last night I ended up measuring R30 at 3.1k, I will check R40 but it appears ok to look at.

Thanks Jim yes I have the 229 prefix manual. Apologies I measured R30 late last night as 3.1k, I will check R40 now and the ripple when I get the 2 pots back in.

Another useful page in the manual is the one quoting resistance (cold) and voltage (hot) values at the tube sockets. The cathodes (pin 3) of the 6CW5's are merant to be 12K to chassis which would not

I am in need of a test fixture for my 1MHz HP 4271B LCR meter, a Hamfest find which I just fixed. Does anyone know if the Tonghui test fixtures work at this freq? TH26001A or TH26029 (with tweezer

Dear All, Finally I collected all things for my 4274a with high voltage measurement. The high voltage card working fine, but I can use it only on lower ranges in capacity mode. Video show what

Just a general general questions on replacing the paper caps. Does it matter if the replacement caps are placed with their foil side orientated in the same direction as the old caps? I know in audio

Hi Roy, Well you might be lucky and I assume you've looked to see whether the PCB is still available from Keysight? Probably not, as the 3245A is so old, but maybe. Otherwise, you might need to fix

Yes, those are all DC voltages. First, are you SURE that the manual you are using is correct for YOUR 200CD. Check the serial prefix on the serial number plate and compare it to what's listed on the

The 6268B (and similar models) holds up well in adverse conditions, and many pallets full of them have been sent to our military in Irag and Afghanistan for those "wars". I still see requests for them

Bonjour à tous We manufactured transformers since 1970s, and did not suffer magnetosstriction noise, as the lamination was secured tightly and usually vacuum varnish impregnated. I have fixed loud