Pentranic CH-288 issue

Lescell

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Pentranic CH-288

The chassis fell off of the frame and shorted out on the tube (monitor was mounted upside down in the cabinet for some reason). This popped the fuse but also shorted out the k1507 transistor on the aluminum shroud (which is probably what popped the fuse). I replaced the k1507 but it shorted out again and popped the fuse. I pulled the c4742 again (HOT) and it's not shorted but the readings make me think it's not in spec. Aside from that, any other suggestions on what to check next so I don't just start shotgunning parts?

Thanks
 
The 2SC4742 transistor datasheet ( https://datasheetspdf.com/datasheet/2SC4742.html) shows that there is a resistor between the base and emitter, so this will not test the same as a traditional BJT.

Since the chassis fell and shorted Q501, you need to check the other components of the SMPS (switch mode power supply), especially those on the primary side of T501. Also check T501 connections for cracks.

Family tells me a been a bit damp up your way, and more coming. Stay dry. :)
 
Checked out the HOT per suggestions from Richard48 and it looks good. No direct ground short to Q501. BD501 also checks out ok.

The only thing I'm noticing as unusual to my novice brain is a direct ground "short" to both base and emitter contacts on the board with the HOT (C4742) removed.. should that be expected?
 
Checked out the HOT per suggestions from Richard48 and it looks good. No direct ground short to Q501. BD501 also checks out ok.

The only thing I'm noticing as unusual to my novice brain is a direct ground "short" to both base and emitter contacts on the board with the HOT (C4742) removed.. should that be expected?
The schematic will show that the emitter is tied to ground and the base is tied to ground through the secondary of the horizontal driver transformer, which is very low resistance. So, normal to read a very low resistance from base to ground.

I've been on travel (including central CT visiting family), so didn't get back to you sooner.
 
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