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   comp.sys.tandy      Life is dandy cuz you're gettin a Tandy!      5,684 messages   

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   Message 3,936 of 5,684   
   Mark Whitlock to Knut Roll-Lund   
   Re: M4 power issue   
   23 Feb 06 22:01:23   
   
   From: markw@abs.net   
      
   Knut Roll-Lund wrote:   
   > Doug_M wrote:   
   >   
   >> Hi, I have a 4D with an Astec power supply.  The power supply "sizzles"   
   >> first for about 30 seconds before the system comes on.  Once it is   
   >> warmed up it turns on immediately.  The person I bought it from sent me   
   >> a replacement Astec power supply.  That was some time ago.   
   >>   
   >> I only just got around to swapping out the old supply for the new.  When   
   >> I turned the system on there was nothing, no sound, smoke, smell, spark,   
   >> etc. and neither the monitor or drives come on. Completely dead.   
   >>   
   >> I thought maybe the new Astec supply was dead, so I put the old one back   
   >> in.  Same thing.   
   >>   
   >> I've got a multi-meter but I really don't know what I'm doing with it   
   >> (just bought it, don't know much about electronics).  I check the on/off   
   >> switch, and it works. I check the wires from the switch to the power   
   >> supply and they're live.  I checked the posts on the power supply and   
   >> they are live too.  So are then leads to the mobo and CRT.   
   >>   
   >> I'm stumped.  Any hardware gurus out there that can point me in the   
   >> right direction?   
   >>   
   >> Thanks,   
   >> Doug   
   >>   
   >> PS  Both the CRT and PS fuses are good too.   
   >   
   > Try wriggeling (check) the cables to the video card (might have been   
   > pulled slightly when opening it...). The edgeconnector there is quite   
   > loose both on my III and (regular) 4.   
   >   
   > Knut   
   Doug,   
   	The leads to the mobo & crt are they 5VDC & 12VDC + or -   
   1/2 volt? Your meter should have a DC & an AC setting. the DC   
   may be marked by a long line with dashes underneath .and the   
   AC may be marked by a sine wave. Check the molex connector   
   (that rectangular white thing with 4 holes) on one setting (DC)   
   then on the other (AC). The readings should be 5 & 12 DC   
   this shows the regulator is working ,and 0 AC this shows the   
   rectifier is working (may depend on meter). The "sizzling"   
   bothers me ,are you sure this was from the power supply and   
   not the (video board) flyback transformer ?   
   	BE VERY CAREFUL WITH THE TOP OPEN the CRT may have   
   5000 volts on it WHETHER ON OR OFF !   
   Stay away from the CRT it is not always your friend.   
   	Please get back to us ,The first sign to look for   
   is the filiment in the back of the CRT tube ,It should   
   be glowing orange (near the end of the tube where it plugs in).   
   Certainly we can narrow this down some.   
   Hopefully helpful,   
   	Mark Whitlock.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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