Panasonic TR-904R help

[Dave A]

I have this little Panasonic 9" B&W with AM/FM in a sliding door, wood cabinet. Cute little thing. The CRT is tired and needs to be Beltronized. It has no info inside and the CRT is behind way too much to pull to ID it.

Does anyone know what the CRT is and what the pinout might be? Looking for filaments, K and G1 only. I have to use the clip leads for this one. It's a sub-miniature 7-pin base.

Wiring is BL, R, OR, YL, WH, GR if there is a common wiring scheme.

Dave A

[Findm-Keepm]

It'll have a 230mm CRT - most Japanese (Hitachi/Matsushita/Toshiba/NEC) follow the same basing as their JEDEC (US) counterparts for their monochrome tubes.

Sphere Research has a Toshiba CRT manual hosted on their site:

http://www.sphere.bc.ca/test/crts/to...rt-catalog.pdf

It has has a 230mm (9") monochrome CRT shown with pinout E7-91 / 7GR (the standard for 7 pin BW tubes):

Filaments 3/4
Cathode 2
G1 pin 5 or 1 (interconnected on some tubes, but not all)

Hope this helps

Cheers,

[Dave A]

Brian,

That info did the trick! Pin 5 for the G1 to be exact. The odd thing is that it indicated as a 12v tube. Nothing below that and went up to 15v. I went with that and did no damage and the filaments looked ok. The old pix was grey mush.

I could not get to the sphere website without a computer lockup. I pressed on in the dark.

I cooked it at 15v for a bit and got about a 15% indication on the meter. Very dead. Shorts removal did nothing.

A long stay on the rejuvanation plug with the Beltron cut-and-repower format got it up to about 40% on the rejuv meter which got it back to useable condition. The life test showed very good with a 17 second hold before drop-off. 10 seconds is the Beltron standard. Fairly bright and no blooming with good contrast and focus. Not 1984 standards, but ok for me.

Some tuner cleaning and some vertical adjustments will follow along with pix when I get a good signal.

Beltron rules! Regards,

Dave A