V2000 R900 very very hot

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Hi;
I am troubleshooting a V2000 HV cage and R900 is getting really hot. Everything seems to be running normally, great pic, HV diode is about 75 Deg. F but R900 goes up from room temp to about 250 Deg. F. in about 90 seconds, then I shut down the monitor, I don't want to kill anything........

My question is, does anyone know what the operating temp of this resistor should be??

Thanks in advance.
Jeff
 
Hi;
I am troubleshooting a V2000 HV cage and R900 is getting really hot. Everything seems to be running normally, great pic, HV diode is about 75 Deg. F but R900 goes up from room temp to about 250 Deg. F. in about 90 seconds, then I shut down the monitor, I don't want to kill anything........

My question is, does anyone know what the operating temp of this resistor should be??

Thanks in advance.
Jeff

I found this info about that resistor here

http://pdf.textfiles.com/manuals/AR...XY (Version 1.1 dated 7 Feb 02) [English].pdf

Under the title . . .
THE HIGH VOLTAGE GENERATOR - OR - EHT SUPPLY ( . . .Page 7)

In particular this part
The input to the EHT supply is at pin eight of P900 where 40 volts AC is fed through a large
resistor, R900. Actually, this is a VERY important resistor because it limits, or regulates, the
current to the oscillator, keeping it from taking off on its own and increasing the high voltage to the
point where X-rays are emitted from the CRT, which is DEFINITELY NOT GOOD.


Also: this may help
http://ebookbrowse.com/gdoc.php?id=75606&url=5301048a87f5538447e75731389d04ea (Wells Gardner V2000 Manual/Schematics, Go to page 9, HV Hold Down, could be exactly what you need)
 
Last edited:
Dez;
Thanks for the info.
I have been monitoring the voltage during the temp. rise and it is constant.

The voltages are as follows:
~40vdc @ pin 8
~38vdc on one side of R900
~25vdc on the other side of R900

These voltages remain generally constant yet the temp of R900 steadily climbs. I let it go to about 325 deg. F. then shut it down. I am using my Fluke IR gun so maybe the temps are a bit off but I did the 'ol wet finger tip trick and it sizzled immediately, very very hot.

I shot the HV diode and it remains around 80 deg. F.

BTW, the cage has been rebuilt, new LESR caps, transistors and diodes......

Jeff
 
Dez;
Thanks for the info.
I have been monitoring the voltage during the temp. rise and it is constant.

The voltages are as follows:
~40vdc @ pin 8
~38vdc on one side of R900
~25vdc on the other side of R900

These voltages remain generally constant yet the temp of R900 steadily climbs. I let it go to about 325 deg. F. then shut it down. I am using my Fluke IR gun so maybe the temps are a bit off but I did the 'ol wet finger tip trick and it sizzled immediately, very very hot.

I shot the HV diode and it remains around 80 deg. F.

BTW, the cage has been rebuilt, new LESR caps, transistors and diodes......

Jeff

What's your HV sitting at (KV)
 
The voltages are as follows:
~40vdc @ pin 8
~38vdc on one side of R900
~25vdc on the other side of R900

Jeff

Just did some calculations (Ohms law)

P = V x I
So . .
P= V²/R
The resistor is 15Watt (P) and it's value is 21Ω (R)
The Voltage across it, you said was 13VDC
So . .
P = 13 x 13 /21
P = 169/21
P= 8 Watts

Since the Wattage is 15W, nothing will happen.

If the voltage across R900 doubles to 26V, you have a problem
 
Did you ever find a solution to this issue? My R900 gets VERY hot as well then after a few minutes starts causing the screen to bloom.
 
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