ON561 double FET

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More pictures of schematics.
 

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I also have a Pm3226, which was given to me has a get you started.

The screen lights up with a vertical broad line, but won't move on the horizontal at all. If we find a replacement to the transistor in question would this be a maybe fix.

Sorry if it sounds dumb, but I'm only just getting into electronics and my understanding is not that good yet.

Richard
 
Scope problem? No really.

Hi!

This problem doesn't sound like one I've had.
If You can not control horizontal speed of a dot on screen then the problem is in timebase sawtooth generator. Then, the problem is affecting both beams. Since the line is vertically broad then I guess that You have some noise in timebase.
Now, since You do have a vertical line toom you do have some noise in vertical amplifier too which tells me that those FET's are ok.
This "noise" that I'm referring to might be oscillations due to false capacitance, dirt nad corrosion related. You'll need a good cleaning agent and another oscilloscope to find tne problem.
As You can see in earlier posts these oscilloscopes are pretty straightforward you should not have much problems with those.
(except tracking some obsolete bits )
Good luck.
 
supplier for ON561 and more

Stumbled upon this thread only now,
I know a supplier for the ON561 matched FET pair, aswell as other vfery obscure parts.
It's here: hxxp://www.arp-electronics.nl/pages/transistors.html

The store is located in the Netherlands, I know the shop is a bit hard to reach since the owner has just recently been hospitalized, but check it out. This guy has a huge collection of hard to get components.

Hope it's of any help,

Jeroen
 
ON 561- Philips PM 3226

Hello, here I leave the service manual for Philips PM 3226, ON 561, you can replace two FETs BF245 or similar, but you must choose 2 of identical features, buy a few, and trace the curve of each and choose 2 identical.
 
That scope and similar was one of the worst scopes I ever used. It wasn't just one, it was all three that were purchased. The trace was not crisp and never was.
 
Hi,


Big guess here based on quick review of the problem, but if this FET is used for the main scope input then if you use two mismatched FETs the worse that would probably happen is you might experience some zero drift as the scope heats up and if the room temperature changes. It might not be that much however and would only require readjusting the DC zero of the scope for that channel once in a while.
 
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