27 Dec
2005
27 Dec
'05
7:29 p.m.
I've powered up the SOL-20 and nothing smoked :)
First, I pulled the 17,000uf and 54,000uf electrolytic cans, and
worked them up to 15V through a 10K resistor. I later stepped this down
to 1K. I let each cap "cook" for about 48 hours. I did this while I
was waiting for an ESR meter I ordered to come in. <URL:
http://clientes.netvisao.pt/greenpal/evb1.htm > The meter arrived
today, and I checked the two big caps and the two 2500uf caps on the
power supply board. They were right in spec.
I then reinstalled the caps and disconnected the supply from the
motherboard and the riser card, then powered it up through a variac.
The supplies looked good, so I plugged them into the motherboard and
riser, attached a monitor (which I first had to get working...) and it
sorta came up.
I appear to have a bad 2102L in the video memory. Bit 0 was always
on, and the problem followed moving the chip. The keyboard is dead,
except for the LEDs. The next post has a question about that.
--jc
Doc Shipley wrote:
Allison wrote:
Anything under a 20W appliance bulb initially. The lower the wattage
the higher will be the initial resistance and lower peak current.
I'm ready to begin the power-up process with this Cromemco Z-2D.
The cards all look good, the backplane and cabling all look intact,
and the PSU itself looks clean and shows no scorching or other
damage. Oh, and I've cobbled up a power cable for it. ;)
I understand the principle of using a light as a current limiter,
but I have one question - say I start with a 7.5W bulb, how long
should I run the PSU at that level, and should I then step up through
20W, 40W, etc? If so, I have bulbs up to 200W; where should I stop?
Doc
S100 linear supplies are unregulated (usually) before they get on
the bus
so a load is NOT needed. Do insure the caps are discharged before
inserting
any board.
Allison