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Magnavox mdr557h/f7 dvr

ennisdavis

Sep 19, 2017
1
Joined
Sep 19, 2017
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having a problem with the power board with this unit. Blows fuses. Caps and diodes good. Mosfet good. Cant find schematic or replacement parts.
 

73's de Edd

Aug 21, 2015
3,613
Joined
Aug 21, 2015
Messages
3,613
Sir ennisdavis . . . . .

To confirm that you are using the proper time lag fuse replacememnt . . . . to further save any more power components from getting crowbarred.
Locate a desk, torchiere or drop light that accomodates conventional screw in based incandescent bulbs.

Place a 60 or 100 watt lamp in it and plug in and turn on . . . let there be light ? . . .then unplug and head for the DVR and use 2 test leads . . . . with their end clips . . .thereby . . . being able to connect the lamp in place of the fuse at the fuse clips.

Plug in and turn on the unit to see if you get a normal cherry red glow as the FWB is charging up
the main 470 ufd raw DC storage cap.
As its degree of charge maximizes . . . the lamps brightness diminishes.

OR . . . . if you have bad power supply parts, the lamp will light up and stay at almost normal 60/100 W brightness.

To be continued . . . . . tune in . . . . . same time . . . . . same station . . . . tomorrow.

73's de Edd
 
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