--------------------------------------------------------------------------- ** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org ** Please direct other questions, comments, or problems to chris@westnet.com Received on Thu Apr 12 14:50:48 2012A 361-2 crosses to an NTE50 which is a 100 volts PNP part. The 926 is probably a date code (June of 1992?).
On Apr 12, 2012 11:10 AM, "Pat Danis" <patdanis@verizon.net> wrote:
Well, I replaced Q606 just in case it was bad. I rechecked all components in the circuit and all tested good. However, Q603 (and Q703) were different transistors than anything I had come across in the past.
I missed them on my first go around on repairs and noticed this time that they were TO-220 packages instead of the smaller MPS-U57/U07 variety. This particular transistor is marked 361-2 and on the bottom of the chip, the Motorola symbol and 926 and what appears to be a smaller font capital "L". These are mounted on the standard heat sink but have a cutout to accommodate the larger transistor. They appear to be some sort of factory replacement. Has anyone seen these before and could you shed some light on their tolerances? I could not find a datasheet on them. Here is a link to the photo of the transistor in case you are curious:
https://picasaweb.google.com/pdkomodo77/WG6100Transistor?authuser=0&authkey=Gv1sRgCI--nZejz7ickAE&feat=directlink
I went ahead and replaced Q603 with a spare from a parts board in case these are out of tolerance for the application. I left the Q703 as-is to see what happens there.
Thanks for your help on troubleshooting this. I guess it was just a bad transistor stuck open. It seems to be running at normal temperatures now. I left it on all night just to be sure.
Pat
On 4/3/2012 2:45 PM, Patrick Danis wrote:
Thanks Bill. I will report back with my findings after I troubleshoot. Wish I had stayed an EE major at school.---------------------------------------------------------------------------
Pat
On 4/3/2012 12:23 PM, wboucher6@cogeco.ca wrote:
Unfortunately, there are several things that could cause Q606 to be stuck turned on. I'll assume that Q606 is in fact
good and not leaking like crazy. Be aware that it might operate/test okay when cool and go into thermal runaway once it
warms up enough. In that case, you'd also get a picture for a while and I assume you are not.
Faults that will cause your described condition:
- an open diode at D600, D601, or D602
- an open R611
- an open Q603
- a shorted Q601
- opens at any of R602, R604, Q602, R605
Bill Boucher
http://www.biltronix.com
Been fixing 6100's for some time and this is the first time I have run---------------------------------------------------------------------------
into this issue. I have a monitor that was brought to me with the
following problem. Q606 is getting extremely hot. So hot that the
transistor socket is turning black like burnt toast and the frame is
almost too hot to handle on the right hand side.
Believe it or not, the transistor is still working. I have been through
the deflection board several times and found nothing. I did find both
power transistors bad so replaced those and the blown fuses and the
socket on Q606 and it still will not come up. I only spent a few
minutes on it as I had to leave town for business. I'm just curious
what would cause the transistor to get so blasted hot.
I will be getting back to it on Saturday to troubleshoot some more.
Pat
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