derekp@gvlf9-m.gvl.unisys.com (06/12/91)
I bought a powers supply that was supposed to be for a 3b1, for a spare. Last night (quite hot) I encountered the mysterious fan speed up/slow down problem for the first time, so I went to replace it with the AC fan. This is what causes me to ask the great questions: 1. The fan didn't do the speed up slow down trick until after installation of a combo card (in slot 0) AND the occurance of a hot day (No its not in an air conditioned room, no I don't leave it on all the time) Is there a connection with the combo card, and slot 0 (under the power supply). There was not a lot of dust under or in the fan. 2. The power supply: The one I bought was marked Power Systems: pn PS-1569 5v/20a 12v/3.5a -12v/100ma. What I foud went I went thru the fan exercise (my supply, which is functional) Power Systems: pn PS-1610-1 5v/20a 12v/5a -12v/300ma. What is a proper PS for a 3b1. (67 meg drive 3.5 meg ram 1.5 of which is on a combo card) Did I buy a 7300 PS? Thanks for any info...
wgs@cuuxb.ATT.COM (~XT6562000~Bill Simeon~C82~rfe~xxxx~) (06/13/91)
In article <1991Jun12.125517.9615@news.gvl.unisys.com> derekp@gvlf9-m.gvl.unisys.com () writes: (Preliminary stuff deleted) > 1. The fan didn't do the speed up slow down trick until after > installation of a combo card (in slot 0) AND the occurance of > a hot day (No its not in an air conditioned room, no I don't > leave it on all the time) > Is there a connection with the combo card, and slot 0 (under the > power supply). There was not a lot of dust under or in the fan. The DC fans in the 3b1/7300 are dual speed fans. When the temperature inside the case raises above a set level, they speed up. When it drops, they slow down. This does NOT indicate a problem, either with the machine in general or the power supply in particular. > 2. The power supply: The one I bought was marked > Power Systems: pn PS-1569 > 5v/20a 12v/3.5a -12v/100ma. > > What I foud went I went thru the fan exercise (my supply, which > is functional) > Power Systems: pn PS-1610-1 > 5v/20a 12v/5a -12v/300ma. > > What is a proper PS for a 3b1. (67 meg drive 3.5 meg ram 1.5 of > which is on a combo card) The proper PS for a 3b1 is the 300ma. supply. > Did I buy a 7300 PS? Yep, you did.
beyo@beyonet.UUCP (Steve Urich) (06/14/91)
In article <1991Jun12.125517.9615@news.gvl.unisys.com> derekp@gvlf9-m.gvl.unisys.com () writes: [Fan stuff deleted] > 2. The power supply: The one I bought was marked > Power Systems: pn PS-1569 > 5v/20a 12v/3.5a -12v/100ma. <*> This is a PC-7300 195W PS. -12v should be 300ma. > Power Systems: pn PS-1610-1 > 5v/20a 12v/5a -12v/300ma. <*> This is a 3b1 2meg motherboard PS at 245w. From what I can see the difference between the 2 PS's are as follows: PC-7300 195w UNIX-PC 245w. ----------------------------------------|------------------------------------ Q1: JE8503 | MJ12005 /w larger Heat Sink R6: 1.5k @ 2W (2W guess) | 1.5k @ 5W (5W guess) C102,103: 470uF @ 50v (BOTH) | 10000uF @ 6.3v (BOTH) Q101: 1 less Heatsink | 1 added Heatsink CRB101: 30CTQ030 | MBR3035PT C111: 470uf @ 50v | 2200uf @ 25v The above info is from looking inside my 3b1 and my pc-7300. This was a visual only comparision. I don't have any prints for these units. NOW!!!! If only someone with Repair manuals can identify these parts then everyone could upgrade there pc-7300 PS :-). For the Q101 Heatsink you could use the black side of the old Q1 sink :-). Then someone would be able to start a group upgrade with the correct info for all those wishing to upgrade there PC-7300 PS for RAM,HD's more Boards, etc UPGRADES. Steve Urich WB3FTP
dnichols@ceilidh.beartrack.com (DoN Nichols) (06/14/91)
In article <171@beyonet.UUCP> beyo@beyonet.UUCP (Steve Urich) writes: > NOW!!!! If only someone with Repair manuals can identify these > parts then everyone could upgrade there pc-7300 PS :-). For the > Q101 Heatsink you could use the black side of the old Q1 sink :-). Unfortunately, the Tech. Ref. Manual does not contain schematics of the power supply. That was a unit supplied by a different manufacturer, so there were no released schematics, and perhaps none available to Convergent. Anybody feel like doing some tracing? DoN. -- Donald Nichols (DoN.) | Voice (Days): (703) 664-1585 D&D Data | Voice (Eves): (703) 938-4564 Disclaimer: from here - None | Email: <dnichols@ceilidh.beartrack.com> --- Black Holes are where God is dividing by zero ---
beyo@beyonet.UUCP (Steve Urich) (06/16/91)
In article <1991Jun14.034234.17406@ceilidh.beartrack.com> dnichols@ceilidh.beartrack.com (DoN Nichols) writes: > Unfortunately, the Tech. Ref. Manual does not contain schematics of >the power supply. That was a unit supplied by a different manufacturer, so <*> Unbelievable! What about the UNIX-PC Service Manual OC: 582-602-030? >there were no released schematics, and perhaps none available to Convergent. <*> The Power Supplys were made by Power Systems Inc. Anyone know if they are still in business? The only thing that I'm worried about is that CRB101 component. I'll take a "CET" guess and say that its the bridge rectifier location. For one of the higher voltages? The rest look pretty easy to get! Steve Urich WB3FTP