Main > Monitor/Video Forum
Hantarex MTC 9000 image squashed vertically
be77amyX:
I'm definitely gonna look into that if I don't have any luck soon! Scrapped the probes I was using with 2" of exposed metal tips and brought my fluke home so shouldn't be shorting anything now.
Current state of affairs is monitor powers on for split second then goes off. lifted D10 and power stays on. B+ is now 130v, also 130v at TR15 HOT. TP14 reads 245v (way high should be 190?) tested TR14, TR18, c40, c41, c36, r74, r77, d12, d13. All good. Gonna carry on checking components in this area unless there's some specific ones I should be hitting?
Also don't get a picture but if I turn screen control up on the LOPT I get a single horizontal line. Does this mean the LOPT is OK or can I not make that assumption?
grantspain:
do you mean vertical deflection failure, is it mounted like a normal tv?
the worry for me is every time you touch this you make it worse, i want to help but not help you destroy it
be77amyX:
Yeah it looks like vertical deflection failure but only when I turn the screen control up. otherwise it's completely black.
Admittedly there's been a learning curve but I think we're making progress here! I'm learning a lot about how this stuff works and how not to test it!
Can I assume LOPT is Ok and the fault is within the vertical circuit? ie. around IC1? would the vertical deflection failure cause the over voltage protection to kick in?
grantspain:
you should be looking at the 24 volts to the vertical ic, there is a safety resistor on the 24v line which i expect burnt out when you shorted the yoke- see if you can find it on the schems
and yes there is a scenario where the 24v missing will cause the x-ray protection to kick in
be77amyX:
Looking at the schem I'm thinking R94 or R6 could be the safety resistor? R6 was ok, R94 was open (~5Mohm). Checked against my donor chassis and the resistor in R94 is physically larger but also seems to be out of spec at 14 Ohm? Gonna have to order a replacement, The schem says 1/2 watt, Is that the size you'd recommend?
Edit: been looking around for a replacement and seems to be recommended to use 1w. Is this a suitable replacement https://uk.rs-online.com/web/p/through-hole-fixed-resistors/2140813/