To EHT, or not EHT?

[Down Under]

Hi all,

I finally had some time to work on my Princess Predicta. I have 3 Predictas that I bought on eBay and had shipped to Australia, they're such a great looking set.

I have the Princess, Debutante and the Holiday. I have recapped (mostly) the Princess and I have an interesting problem. If I leave the yoke disconnected, I get a healthy arc from the flyback and a dot on the screen with the gun connected to its socket. Luckily I had the brightness all the way down, I would have hated to have ruined the CRT with a dead spot in the middle!

If I connect the yoke, I lose the EHT, and the 6DQ6 red plates. Boost volts are too low, about 288V. The grid of the 6DQ6 is around -44V. I tried the yoke from the debutante thinking I might have had a short, but same result. The flyback tx readings in terms of resistance measure OK. (I badly need a CRO) I have replaced the sockets of the 6DQ6 and the 6DA$, and pulled the board for a complete examination. A few of the tracks had been (badly) repaired but I cleaned those up. It's very handly indeed to be able to compare readings etc. from the Debutante to the Princess, as I've pulled both boards.

Any info on this issue would be very much appreciated, along with the orig Philco manuals or a link to them. I have the Sams manuals, but I luckily found on this forum the pin location IDs to the main board, which has helped me no end. I bought some push on pins to save a lot of time when removing/fitting the board for testing. A Brother P-touch and lots of numbered labels works very well indeed. The Philco manuals are good in that they match the part numbers listed on the board. Am I the only one who wonders why they used their own numbering system?

Lastly, I'm looking to buy a Mahogany Tandem, but that's for another post...

Cheers,

Adam