Recent content by Scruit

I started typing up a response and I think that myself and VintageVic are answering two slightly different questions. Those two questions are: 1) Does the power supply have a PS_ON pin that needs to be shorted to tell the power supply to turn on, like a modern atx power power supply? Answer...

Any time! Good luck!

I will have to look at the board again and soo if that pinout makes more sense than the standard TO-3 where the case is ground and the two pins are in/out. Thank you! This is a great lead!

- My TL866 II could not read the chip. - The 8042 and 8742 chips had to be read using this reader/programmer: http://www.keeelectronics.com/oscommerce-2.3.4/catalog/product_info.php?cPath=1&products_id=29 I had to buy the optional "MCS-48 Adapter" - this is critical!! - I did not have to deal...

Compaq is definitely not not an unknown brand, but the definitely hold their schematics and part#s close to their chest.

OOooOOOh... "resistive divider" were the magic words. Tracing the circuit shows that both of these TO-3s are in parallel, and they go through independent diodes to the "+12v" and "+12v Mon" outputs. But what I also see is something in that circuit that looks like a resistor array, 6 pin...

I'm going to try wiring it up to my component tester, see if it can figure it out.

Compaq Portable 286 power supply, there are two identical TO-3 packages labelled "102528" with Linear Tech logo. Anyone know what these are?

First timer here also. Awesome show all around. Agree that Ruud and Birt's presentations were very informative - those were the ones I had in mind when I signed up. I'd seen Birt's retrobriting analysis on youtube and appreciated the attention to detail, so he was the main reason I signed...

The crystal tests ok. Tested by building an AD9850-based signal generator and pushing 9mz and 10mhz through the 10mhz crystal. Output jumps when I hit the correct frequency. Actually found the frequency to be 10.001 Mhz Attached imaged show a red trace which is the output from the signal...

I don't have any spare crystals lying around, but ordered a pack of cheap crystals in different frequencies, they will be here in a few days. The two capacitors tested OK on the LCR meter, 20.5 pF, which is close enough given the rating of 20 pF +/- 5%. I am putting together a cheap signal...

Confirmed that there is no oscillation on the XTAL pins of the 80c39. They read 2v and 1v, flat. On powerup they go direct to those readings with no delay, and stay there. The keyboard does not work, even when I got to the 'world map' screen while I had the oscilloscope hooked up, no...

I appreciate your assistance! So, given that the schematic and board don't match in this case, my confusion on inductor vs crystal was understandable, so I don't feel quite so silly. :) However this inductor/crystal is the first inconsistency I have noted in the schematic compared to my...

You are correct, I need to look closer - the concept is clearly not as simple as I had thought.

That is the chip. Y2 is an inductor? I thought it was a crystal oscillator... In my mind the difference was that a "clock signal" is what I would call something that had more of a square wave, and the "crystal oscillator" was the silver component (usually with a frequency printed on it)...