Hi, im working on a dead Hantarex MTC9000 monitor.
When starting it up I have ~130VDC on the yoke connector (black wire), I can hear high voltage static but then quickly I can hear the tube discharging.
Replaced the chassis with a known working chassis but got the same result.
The yoke seems to be fine, 2.5 Ohms and 14 Ohms.
I the put the previous known working chassis together with another tube, but then I got the same symptom, HV static, discharge but still 130VDC at the yoke connector
Is there a short in the first tube that killed my second chassis?
The first chassis has an original Eldor flyback, which are prone to die.
Calling mr @grantspain and @PrincessPrinPrin
Hantarex MTC9000, shorted tube (no it wasnt) ??
- frsj8112
- Posts: 90
- Joined: April 11th, 2012, 6:06 pm
- Location: Sweden
- eBay: frsj8112
Hantarex MTC9000, shorted tube (no it wasnt) ??
Last edited by frsj8112 on May 13th, 2021, 10:02 am, edited 1 time in total.
- PrincessPrinPrin
- Posts: 577
- Joined: April 7th, 2011, 4:00 pm
- Location: Pordenone, Italy
- eBay: *mkl*
- Initials: MKL
Re: Hantarex MTC9000, shorted tube??
Lift one side of D10 near the TDA2595 to disable the x-ray protection. If the high voltage stays on (but don't leave it on for more than a few seconds), check if the capacitance of C36 is much lower than 3.9nF and if so replace it.
- frsj8112
- Posts: 90
- Joined: April 11th, 2012, 6:06 pm
- Location: Sweden
- eBay: frsj8112
Re: Hantarex MTC9000, shorted tube??
I’ve looked a bit more at this.
I have a third working mtc9000 (named nr3) in my Operation Wolf cabinet.
I hooked it up together with the questionable tube and it’s working!
Great, tube is ok
However it seems like my previous repaired chassis (named nr2) had failed.
I hooked nr2 up again and desoldered D10. Chassis starts and I have high voltage and get image on the screen.
Most of the polymer caps in the power supply has been replaced previously.
TR15, TR20 is ok
I have a third working mtc9000 (named nr3) in my Operation Wolf cabinet.
I hooked it up together with the questionable tube and it’s working!
Great, tube is ok
However it seems like my previous repaired chassis (named nr2) had failed.
I hooked nr2 up again and desoldered D10. Chassis starts and I have high voltage and get image on the screen.
Most of the polymer caps in the power supply has been replaced previously.
TR15, TR20 is ok