Junebug VPP short

[blueroomelectronics]

the small inductors will make it work harder to maintain VPP. The lowest I've used is 470uH and that works fine.

 

[skyhawk]

I bought my inductors from Futurlec. There were $.18 a piece, so I bought ten. I've built 3 programmers and may build more to give to others. Futurlec ships from Thailand. It's hard to believe you can't buy from Futurlec.

https://www.futurlec.com/Inductors.shtml

 

[mvs sarma]

Mvs,

I'm in trouble. The maximum inductor value available here is 100 uH. That's simply not enough.

MVS told me I can use a transistor radio IFT in place of the inductor.
In those IFT's, there are two pins in one side, and other side has three pins.
So, where to connect;in the two pinned side or the three pinned side??
I'll remove the metal exterior, the tuning mechanism.

What things to be checked for Vpp error? I think :

the PNP transistor, the inductor, the IN4148 diode....any more??

and I use BC548B transistor in all NPN transistor places, which were 2N3904.
I use BC558 transistor in all PNP transitors places,which were 2N3906.
Both have reverse layout. ie C-B-E. the 2N390x have E-B-C layout.

Any problem...any suggestions???...Hope Mr. MVS will solve the IFT problem...

680uH coils are extensively used on the B&W Portable TV at the Video amplifier front end transistor collector. also on ET&T TVs picture tube grid transistor collector. and on color picture tubes Neck board, you find three of them.
These are sold as spares in the TV service shops. On a 10mm drum core if you use 33swg wire and wind 200 turns, you get approx 680uH.

Filtronics of Kolkatta is making all sorts coils as a friend of mine told me.

The best appears to contact a local TV repairer and search for one such coils explained above.

If still a problem is faced, Should I send you 10 of them would for you please? If you need from me you may PM your address to me and rest, I shall take care of. I can't imagine Bill's board lying idle.

 

[mvs sarma]

Mvs,

I'm in trouble. The maximum inductor value available here is 100 uH. That's simply not enough.............
Any problem...any suggestions???...Hope Mr. MVS will solve the IFT problem...

your coils are ready and i don't have your postal address?

you mat send PM to me you postal address and phone number. I can send by courier.