Sencore VA62 ring test on 40's flybacks

[Phil]

I wonder if anyone else has used a VA62 to ring older flybacks, specifically those from late '40's RCA sets? I am currently working on a 9T240, 8T241 and 648PV, all of which have very similar flyback construction. I have 3 horizontal sweep/HV chassis for the 648PV. All 5 of the flybacks in question check bad according to the VA62. I have several flybacks, circa 1955-1965 and have checked many of them with the VA62 and it checks them all as good. (These are all NOS) I bought a HVO10 Merit universal flyback for the 9T240 and it checked bad out of the box (it was used). I put it in the set anyway and it works, so obviously it is not bad. I also note that on all of these the highest ring number I get is with the impedance matching switch in the greatest counterclockwise position. I'm beginning to think perhaps the VA62, which came along long after there would have been much likelihood of 1940's sets coming into a shop, might not have enough impedance matching range to properly test these transformers. Has anyone else experienced this? Thanks to Electronic M, aka Tom C., for questioning my tests validity which made me question this more thoroughly. Btw, I'm testing these out of the circuit and near no metallic objects which might load them.

[bandersen]

Yes, I have tried using a V62 on late 40s - early 50s and found the results to be very inconsistent. I went through a dozen that were all used but worked fine in a set and got a lot of bad ring tests.

I had more luck with an EICO 944 which is much earlier than a VA62.

My conclusion was that the best tests for early flybacks is if the DC resistance matches the schematic, try it in a set.

[Tim Tress]

How about the Sencore YF-53? I got one at an estate sale a while ago, but haven't tried it out yet.

[arts]

Originally Posted by Tim Tress

How about the Sencore YF-53? I got one at an estate sale a while ago, but haven't tried it out yet.

Tim,do you mean YF33? And if you do,do you have the manual for it?