33V stabliizsers - PH33J AND 33G - differences?

Generally speaking you can use any of the different manufacturers parts so long as its specified for use as a 33V tuner varicap supply stabiliser.

On Wed, 25 Feb 2009 04:32:14 -0800 (PST), b put finger to keyboard and composed:

Are you sure?

The following forum thread suggests that the PH-33J is equivalent to the BYD33J, in which case your diode is not a "stabiliser":

This site lists it under Schottky diodes:

Confusingly, this stock list shows a PH-33V as a 33V 1W part:

A typical use for a 33V stabiliser would be in the tuning voltage supply. Is this where it is used?

This list of Philips marking codes attributes a code of "33J PH" to the BYD33J (fast soft-recovery controlled avalanche rectifier):

Here is a datasheet for the BYD33 diode:

Assuming your PH33J is a Philips part, as suggested by a search at

then the above datasheet suggests that the suffix denotes a particular rating, in this case the VRRM.

VRRM repetitive peak reverse voltage

------------------------------------ BYD33D - 200 V BYD33G - 400 V BYD33J - 600 V BYD33K - 800 V BYD33M - 1000 V BYD33U - 1200 V BYD33V - 1400 V

While the same suffix for a zener would be comparing different parameters, it would at least appear that the J part has a better rating than the G part.

- Franc Zabkar

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Please remove one \'i\' from my address when replying by email.

"stabiliser":

diodes:

part:

Thanks a lot for all the info. Hmm, looks like it may not be the right thing.

Yes, this is in the 33v line to the tuner of the TV. it is replacing a TAA 550. (symptoms: set searching but not finding anything, just snow. Tuner supply down to about 5v) not only that, but I fitted it this afternoon and tried the set, I got a picture but tuning lock was unsteady especially when channels were changed. To my surprise I measured some 50v on that line instead of the usual 30v! Obviously something is amiss. Apparently I can use a KA33V stabilizer in lieu of the TAA 550, so I'll get one and see.

-B

On Wed, 25 Feb 2009 13:54:03 -0800 (PST), b put finger to keyboard and composed:

"stabiliser":

diodes:

part:

The 33V supply is probably derived from a rectified 50V pulse from the flyback transformer. It most likely consists of a rectifier diode, capacitor, series resistor, and the TAA550 33V precision zener.

If a reverse biased rectifier diode were installed in place of the original TAA550, then the full 50V would have appeared on the supply rail.

- Franc Zabkar

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Please remove one \'i\' from my address when replying by email.

"stabiliser":

diodes:

Some TVs use this (33V part):

I think that is what I mistook that part for. There is one thomson chassis which uses it.

Anyway, after replacing the susepct regulator with the KA33V all is well.