GE VG4025 / RCA VR507

B

BFriedl

Guest
I've got this GE VG4025 (dont know chasis) that is having SMPS problems.
When plugged in, capstan pulsates at about 1hz. After about 3 minutes of
this, the display starts to flash POWER/VCR LEDs in sync with capstan
pulsing. I searched for VG4025 and got this webpage and content:
http://intrepid-video.com/database/genelectric.htm
VG4025(VR507)
*Dead
*C08 in power supply

*Dead, timer flashes, won't accept tape
*C09(22/16v np), C04(4.7/25v), C05(82/200v)

*At power on capstan pulsates
*C09(22/16v np), C4(4.7.25v)

I replaced C04, C09 and C05, however C05 is 400v (should work, right?)
No change in condition. I also noticed that if I manually turn the load
motor to a half-load position, the VCR will power up long enough to
"eject" the tape. If I hold it in place, it will eventually time out,
however now the VCR will work perfectly from a mechanical point. Loads,
Plays, rewinds, seeks, etc.
I stuck a tape in and noticed that it had problems syncronizing the
correct speed and sound would be garbled and slow. Picture also had 4
thin horizontal lines that would roll down. Also could hear motor noise
though speakers.
I dont have a ESR meter (yet!), but have heard that the caps in the
secondary need replacing too? Or is it a diode?
With power supply pulled out of machine, under no load, I am not getting
readings out of the xformer that are silkscreened on the board. Seems
that two of the primary windings are powered, but the windings connected
to the feedback circuit are not.
Any help please!
(hope this post was a good, detailed post)

--
BFriedl
A+ Certified Technician
AIM: UACybercat
** Bear Down Arizona! **
******* Go Cats! *******
 
"BFriedl" <junk-remove-@bfriedl.com> wrote in message
news:b5eUb.20197$tP1.11042@fed1read07...
I've got this GE VG4025 (dont know chasis) that is having SMPS problems.
When plugged in, capstan pulsates at about 1hz. After about 3 minutes of
this, the display starts to flash POWER/VCR LEDs in sync with capstan
pulsing. I searched for VG4025 and got this webpage and content:
http://intrepid-video.com/database/genelectric.htm
VG4025(VR507)
*Dead
*C08 in power supply

*Dead, timer flashes, won't accept tape
*C09(22/16v np), C04(4.7/25v), C05(82/200v)

*At power on capstan pulsates
*C09(22/16v np), C4(4.7.25v)

I replaced C04, C09 and C05, however C05 is 400v (should work, right?)
No change in condition. I also noticed that if I manually turn the load
motor to a half-load position, the VCR will power up long enough to
"eject" the tape. If I hold it in place, it will eventually time out,
however now the VCR will work perfectly from a mechanical point. Loads,
Plays, rewinds, seeks, etc.
I stuck a tape in and noticed that it had problems syncronizing the
correct speed and sound would be garbled and slow. Picture also had 4
thin horizontal lines that would roll down. Also could hear motor noise
though speakers.
I dont have a ESR meter (yet!), but have heard that the caps in the
secondary need replacing too? Or is it a diode?
With power supply pulled out of machine, under no load, I am not getting
readings out of the xformer that are silkscreened on the board. Seems
that two of the primary windings are powered, but the windings connected
to the feedback circuit are not.
Any help please!
(hope this post was a good, detailed post)

--
BFriedl
A+ Certified Technician
AIM: UACybercat
** Bear Down Arizona! **
******* Go Cats! *******

9 times out of 10, with these symptoms, the trouble is caused by bad caps.
Click to expand...
I'm looking at a schematic for a VR507 and it shows C5 as a .0022 Mfd @ 400
volts. If this is correct, you didn't need to change it. (I've never seen
one go bad) An easy way to troubleshoot without an ESR meter is to take a
hair-dryer, heat the power supply until it starts working & then start
cooling caps down, one at a time with some Circuit Cool until it goes bad
again. C15 & C16 usually go bad in this power supply as well as C9 & C4. (If
you want to work on SMPS you really need an ESR meter.)
Good luck
 
Patch wrote:

I'm looking at a schematic for a VR507 and it shows C5 as a .0022 Mfd @ 400
volts. If this is correct, you didn't need to change it. (I've never seen
Look again at my OP:
VG4025(VR507)
*Dead
*C08 in power supply

*Dead, timer flashes, won't accept tape
*C09(22/16v np), C04(4.7/25v), C05(82/200v)

*At power on capstan pulsates
*C09(22/16v np), C4(4.7.25v)

I replaced C04, C09 and C05, however C05 is 400v (should work, right?)
Click to expand...
C05 (not C5) was 82uF 200v. Definately 'lytic and not ceramic in the pF
range. Also was looking for C08 and it doesnt exist!! So you would guess
secondary caps (since I replaced all but 1 primary 'lytic i believe)
--
BFriedl
A+ Certified Technician
AIM: UACybercat
** Bear Down Arizona! **
******* Go Cats! *******
 
Patch wrote:
"BFriedl" <junk-remove-@bfriedl.com> wrote in message

9 times out of 10, with these symptoms, the trouble is caused by bad caps.
I'm looking at a schematic for a VR507 and it shows C5 as a .0022 Mfd @ 400
volts. If this is correct, you didn't need to change it. (I've never seen
one go bad) An easy way to troubleshoot without an ESR meter is to take a
hair-dryer, heat the power supply until it starts working & then start
cooling caps down, one at a time with some Circuit Cool until it goes bad
again. C15 & C16 usually go bad in this power supply as well as C9 & C4. (If
you want to work on SMPS you really need an ESR meter.)
Good luck


Patch, I followed your recommendation, and sure enough, warming up the
Click to expand...
secondary caps for about 2 min resulting in the VCR powering on. While
in playback (still have those horiz bars) I applied some cold air to
C14(470uF, 16v) and the capstan started to slow down and finally
stopped. Repeating the procedure to the other 4 'lytics resulted in no
change. So it looks like C14 is it! Will update when I have solved the
problem (or introduced a new one!)
PS - ended up replacing C05 with what was in there, 82uF, 200v, as it
fit much better and has a lower profile.



--
BFriedl
A+ Certified Technician
AIM: UACybercat
** Bear Down Arizona! **
******* Go Cats! *******
 
BFriedl wrote:
Patch, I followed your recommendation, and sure enough, warming up the
secondary caps for about 2 min resulting in the VCR powering on. While
in playback (still have those horiz bars) I applied some cold air to
C14(470uF, 16v) and the capstan started to slow down and finally
stopped. Repeating the procedure to the other 4 'lytics resulted in no
change. So it looks like C14 is it! Will update when I have solved the
problem (or introduced a new one!)
PS - ended up replacing C05 with what was in there, 82uF, 200v, as it
fit much better and has a lower profile.

Hell yeah! My first succesful repair! All this supply needed was the
Click to expand...
$1.25 C14 cap. Poped it in, and VCR powered up immediately and played
without any noise bars on video, and no motor sounds in the audio.
Thanks Patch for your help.

Case closed.
--
BFriedl
A+ Certified Technician
AIM: UACybercat
** Bear Down Arizona! **
******* Go Cats! *******
 
Oops, forgot to mention that I also repaced C04 and C09 on the primary
side. Dont know if that was part of the problem, but why take them out
to find out? They would have failed in a year anyways.

--
BFriedl
A+ Certified Technician
AIM: UACybercat
** Bear Down Arizona! **
******* Go Cats! *******
 
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