Mtc9000 ? I think ..

[Retroman839]

with all those new parts fitted,someone has obviously had problems with it in the past,did it come to you with a background story?

Only that it was sent of for repair
Came back worked for a short time ..
Like 10 weeks only
Power up and used a few times in those 10 weeks before it just stopped coming on .

 

[Retroman839]

Power supply is ok by the looks of it
Will get a measure of the b+



Good b+

Should be 130v should I dial it up to 130v ?

 

[Retroman839]

I’m thinking of lifting the xray protection diode to see if this circuit is keeping the chassi from coming on .

D10 connected to pin 8 of this
Ic2 tda2529

But its unpopulated ?
No d10 , No r76 or r78 etc. ?

 

[gunblade]

early version 9000 like this one had no xray protection circuit
i would look at r94 and check hv caps plus check the readings of TH1
128v is fine

 

[Retroman839]

early version 9000 like this one had no xray protection circuit
i would look at r94 and check hv caps plus check the readings of TH1
128v is fine

Thanks 🙏
Ok will do that ..
I was just removing one leg of R111 to disable vertical deflection ic and test with ic disconnected as apparently a shorted vertical ic will also trigger continuous loop

Is that something I should carry on and try ?
D19 is 5.6Mohm so that looks ok
Th1 can I check that in diode mode or for shorts ?
Or read is voltage output when chassis is running ?

 

[gunblade]

th1 read with ohms, one side should be around 26 ohms and thats the only side to be concerned about
what does r94 read?

 

[Retroman839]

th1 read with ohms, one side should be around 26 ohms and thats the only side to be concerned about
what does r94 read?

👍

 

[gunblade]

probably ok as should be 3r9

 

[Retroman839]

probably ok as should be 3r9

Should I change it ?

I’m using the top posts of the th1 to take readings ..



Yep got 27 ohms on the left

 

[Retroman839]

I will go ohm the windings of the yoke
Looks ok

 

[gunblade]

c36 read ok?

 

[Retroman839]

c36 read ok?

Do I need a cap reader and remove it for that ?
I have one .. bit dodgy but I can use it .

 

[gunblade]

best to remove and read

 

[Retroman839]

Little
Orange pillow…
Is it on the collector of the hot b+ line ?

Will give it a go ..
0.01k Marked one side
400 mkt 3 I think

 

[gunblade]

no, its the 4n7 1500

 

[Retroman839]

no, its the 4n7 1500

Good … because I couldn’t read that pillow anyways👍

 

[Retroman839]

Gotta get a decent esr meter !

 

[gunblade]

yep, if you going to attempt chassis repairs it's a must
i would have dummy load on the collector of the hot with hot isolated from circuit

 

[Retroman839]

yep, if you going to attempt chassis repairs it's a must
i would have dummy load on the collector of the hot with hot isolated from circuit

When taking readings ?

 

[Retroman839]

Is it posss to know what’s the + and - of this cap
It’s in the post 👍