Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting Power Supplies and Power Supply Design
Register FAQ Calendar Search Today's Posts Mark Forums Read

Thread Tools
Old 06-03-2019, 12:39 PM   #1561
PeteS in CA
Badcaps Veteran
PeteS in CA's Avatar
Join Date: Aug 2005
City & State: San Jose, CA
My Country: USA, Unsure of Planet
Line Voltage: 120VAC, 60Hz & 115VAC, 400Hz
I'm a: Professional Tech
Posts: 2,854
Default Re: the gutless, bloated, and fried power supply hall of shame

ae7oo, if the TL494 clone PWM is on the secondary side then no feedback optocoupler or feedback transformer is needed. The pulse width modulation is done by the PWM IC, which drives the switch transistors.

For having been built in the second half of 2000, that 1A 5VSB is pretty wimpy. The 2SC3866 switch transistor is probably for the 5VSB, while the 2SC4106 switch transistors are the main inverter, probably half bridge. Everything about it screams noisy gutless wonder. Trying to draw 250W continuous from it probably would have resulted in a dramatic event in a matter of minutes or less.
PeteS in CA

Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells.

Where might is right
There is no right.
- Sophocles in "Antigone"
All that is gold does not glitter,
Not all those who wander are lost;
- J.R.R. Tolkien, The Fellowship of the Ring
To kill personal responsibility, initiative or success, punish it by taxing it. To encourage irresponsibility, improvidence, dependence and failure, reward it by subsidizing it.
PeteS in CA is offline   Reply With Quote

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump Technical Forums 2003 - 2019
Powered by vBulletin ®
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 09:06 PM.
Did you find this forum helpful?