PC/AT "power good" problems

[Alexandre Souza]

Put a 10 or 22 uf on the reset connector

Enviado do meu Tele-Movel
Em 28/05/2016 18:38, "Richard Cini" <rich.cini at verizon.net> escreveu:

> All –
>
>
>
> I pulled my old PC/AT off the shelf to see if I could get Windows 1
> running on it (since I just located the Windows 1.04 SDK which I have
> running in Bochs). It worked when shelved years ago, but it unfortunately
> suffered some case damage from a leaky battery. No damage to the mobo or
> cards thankfully. I replaced the battery with a 4-AA pack.
>
>
>
> Basically, the PC won’t come out of reset. I tested the power supply with
> a load tester specifically for PC power supplies and it reports power_good
> and all voltages look good on a meter. So far, so good. I dug out my ISA
> POST diagnostics card which also has a PG tester in it. This reports no_PG
> but I do see the reset pulse on the bus. Not sure why one would report OK
> and one not.
>
>
>
> I have a spare generic power supply (which also tests good using the same
> tester) and produces the same result. I have no cards installed but I tried
> it with floppy/hard drives both connected or not connected.
>
>
>
> I traced the PG signal from the power supply through the 82284 clock
> driver/ready interface chip and the PG is definitely there (transitioning
> L->H on power-on) and RESET is transitioning H->L.
>
>
>
>                 Any recommendations on where to go from here? Does anyone
> have an extra PC/AT motherboard they would be willing to part with?
>
>
>
> As an aside, would this have been a typical development machine? AT was
> introduced in August 1984 and Windows 1.04 was released in 1987 so I’m
> guessing probably.
>
>
>
> Thanks!
>
>
>
> Rich
>
>
>
> --
>
> Rich Cini
>
> http://www.classiccmp.org/cini
>
> http://www.classiccmp.org/altair32
>
>