How to measure B+ on a Toshiba PD2367 chassis

[BuddyC]

Howdy!

Just did a recap on a Tosh PD2367 chassis in my NNC and would like to measure B+ as safe as possible.
Got the equipment and experience to measure, but unsure on where to place the probes for the multimeter.
Please school me!

 

[BuddyC]

Got a reply from arcademaestro Grantspain over at arcade-Otaku.
Copied his replys here just in case anybody else need this info:


Post by grantspain » Today, 4:13 pm
all the digital chassis tend to 175-180v and normally read at the picofuse or safety resistor if fitted

Post by Buddyc » Today, 5:13 pm
Thanks Grant!
So red probe on one of the legs of the pico fuse and black probe anywhere on the chassis mount?
Somebody placed a normal fuse there one time( As you mentioned in my other tread a couple of days ago). Would this be a issue when measuring?


Post by grantspain » Today, 5:18 pm
yes red probe to fuse and black probe to metal frame, pretty sure it will be about 180vdc
the picofuse is a very quick blow type fuse, as long as they put same speed fuse and amp rating in then it will be ok

Post by Buddyc » Today, 5:22 pm
Ps. 180VDC on 31khz, but probably lower for 15khz?


Post by grantspain » Today, 5:25 pm
no i would expect it to be the same on digital chassis for all resolutions as they normally power the video b+ from chassis b+ and that must remain stable.

 

[Piafoman]

Hi !
I would like to update the topic because I can't find the place to take the measurement.

Can someone tell me the location on the chassis?

Thank you !

 

[AlxUnderBase]

Hi !
I would like to update the topic because I can't find the place to take the measurement.

Can someone tell me the location on the chassis?

Thank you !

Red probe where i mark with black colour on the picture attached (there is the fuse) , and black , on the tube metal frame . i put a black line because i didnt know how to change the colour (shame on me)

Glad was pointed by BuddyC. sorry @Piafoman if i was missleading with my notes (i thinked was about that fuse) !

 

[BuddyC]

Hi !
I would like to update the topic because I can't find the place to take the measurement.

Can someone tell me the location on the chassis?

Thank you !

I couldn’t see Alex markings, so I made a reference for you. The picofuse is a tiny bastard so use a crocodile clip for red probe where I marked in red. Black probe goes as shown.

 

[Piafoman]

Thanks men !

AlxUnderBase: with your mark, i have -15 Vcc... (black négative in gnd and red positive in fuse).

BuddyC: I have 177,8 Vcc.
Do you know how variate this mesure ?

I up and down thé pot high voltage or screen of flyback, norhing changement.


Thanks à lot !

 

[BuddyC]

Thanks men !

AlxUnderBase: with your mark, i have -15 Vcc... (black négative in gnd and red positive in fuse).

BuddyC: I have 177,8 Vcc.
Do you know how variate this mesure ?

I up and down thé pot high voltage or screen of flyback, norhing changement.


Thanks à lot !

High voltage adjust (HV. ADJ.) is marked in pic below. Should be 180 VDC so you are not far off With 177,8 VDC

Lots of good info in the link below
https://www.neo-arcadia.com/forum/viewtopic.php?t=48717&hilit=Toshiba+PF+D29C051

 

[Piafoman]

Hi.

Thanks.
No effect, no variate of mesure b+ (177,8 Vcc)
However the image enlarges or shrinks with changing brightness.
Thanks for your answer.,