Anyone had a noisy tube

[Retroman839]

So I just turned on a racing cab
With a SanwA pfx.. for first time

Monitor had really strong neck glow
But the tube was making noise like gas escaping ?
Normally a no signal message on screen
But screen had no sign of life .

Switched off..
Switched back on now chasiss just ticks

Just wonderd anyone experienced this before ?

 

[big10p]

Duff flyback, innit? I guess it's anybodies guess what voltages were coming out of it.

 

[Retroman839]

Duff flyback, innit? I guess it's anybodies guess what voltages were coming out of it.

Has to be the flyback dosent it
Only thing that can really make noise ..
Seemd to me though like it was coming from inside the tube ..
Maybe the high voltage went really high just before dying ..
Now the high voltage protection kicking in so makes sence.

The hissing sound classic flyback..
I was thnking bad tube ..
I can try a good chassis on it

 

[big10p]

Has to be the flyback dosent it
Only thing that can really make noise ..
Seemd to me though like it was coming from inside the tube ..
Maybe the high voltage went really high just before dying ..
Now the high voltage protection kicking in so makes sence.

The hissing sound classic flyback..
I was thnking bad tube ..
I can try a good chassis on it

Yeah, try a working chassis with the tube.

 

[Retroman839]

Yeah, try a working chassis with the tube.

A Chance to use my flyback tester for first time

 

[Lukey13]

Would a hairline crack somewhere on the tube give this kind of symptom if not necessarily necked/properly busted??..

 

[Retroman839]

Would a hairline crack somewhere on the tube give this kind of symptom if not necessarily necked/properly busted??..

That’s what I initially thought
It sounded like the tube was leaking
Or sucking air in? ( Negativly pressurised )
But just a likley is flyback hissing

Will go down the rabbit whole on this one good inspection
Pull the flyback try to work out how to use flyback tester I bought. Check it out

 

[tin]

Arcing flyback for me. I've got a sanwa that does it (and currently still works!) but the air smells mega ozone-y after it's been on for a while which would suggest true same. Not been able to clap eyes on the actual arcing tho yet.

 

[FrancoB]

Cabbage does it to me.

 

[Mc-Q]

a bad tube wont shut the chassis down, you will get arcing inside the neck if you get air in it.

 

[Retroman839]

a bad tube wont shut the chassis down, you will get arcing inside the neck if you get air in it

 

[Retroman839]

I did hear some arching sounded as though it was behind the anode cap

 

[Mc-Q]

thats excessive high voltage, a chassis issue
start by checking the b+ capacitor, the line output transistor and the lopt - as you have a tester

 

[Retroman839]

thats excessive high voltage, a chassis issue
start by checking the b+ capacitor, the line output transistor and the lopt - as you have a tester

I want to power it up once more just to see if it recreates the fault..
Or
If it only ticks then I know at least things have blown.

I have a tester but I don’t know how to use it yet.

 

[Mc-Q]

do you have a chassis schematic?
and what lopt tester do you have? a Konig one with volt display or a "ring tester"?

 

[Retroman839]

This one
Apparently no go on 15khz
But 31 is ok. I’m not sure about the split diode part though?
Need to find out if Pfx lopt is a splity?
I do have a schematic but it’s not clear
There is no clear for this model
SanwA pfx .

I have spare hot & mossfet
Recently I got 2 non working Pfx up and running with help of gunblade .
New hot and mossfet and replaced ceramic resistors for a double value
Than the stock ones .. plus added ceramic heat shield behind the new hot rather than the stock paper or plastic variety.
I have another 3 spares chassis's
1 of which I also did same work to but it gave off magic smoke in around 3 different zones. So something is open on that chasis !

 

[Mc-Q]

whats the transformer number?
i have a cd full of data from konig.
btw how much did the tester cost?

 

[Retroman839]

Part number is
Flyback FUH30A001

I paid £160 for it.

 

[Mc-Q]

you must need to test a lot of transformers to pay that, i built a ring-tester for about as much as 2 beers back in the day

 

[Retroman839]

you must need to test a lot of transformers to pay that, i built a ring-tester for about as much as 2 beers back in the day

I have another little flyback tester as well
Again I haven’t used it and I don’t know how too but will

I have a few monitors that I would love to be able to identify good or bad flybacks