Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Pszemol
 
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Default Common voltages from PWR SUPPLY in VCRs ?

What are the common voltage outputs from the power supply ?
I am repairing my first VCR with power supply issue and
cannot figure out what should I expect in good working one.

I see 21V and -7V and many other pins with 0V.
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Ricky from trailerparkboys
 
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Without experience you should`nt touch the powersupply, ESPECIALLY WHEN
PLUGGED IN could be 120 volts AC(ALTERNATING CURRENT) coming out
(DANGEROUS).
"Pszemol" wrote in message
...
What are the common voltage outputs from the power supply ?
I am repairing my first VCR with power supply issue and
cannot figure out what should I expect in good working one.

I see 21V and -7V and many other pins with 0V.



  #3   Report Post  
Sam Goldwasser
 
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"Pszemol" writes:

What are the common voltage outputs from the power supply ?
I am repairing my first VCR with power supply issue and
cannot figure out what should I expect in good working one.

I see 21V and -7V and many other pins with 0V.


No such thing as "common voltages". What's the make and model?

And, as someone else shouted, do take care around the power supply.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

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Pszemol
 
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"Ricky from trailerparkboys" rplpefkipe@kpo[fg,net wrote in message ...
Without experience you should`nt touch the powersupply, ESPECIALLY WHEN
PLUGGED IN could be 120 volts AC(ALTERNATING CURRENT) coming out
(DANGEROUS).


Relax tiger... I know what the high voltages are, I worked with TV sets already.
There you have much more things to worry about than some stinking 120V ;-)
  #5   Report Post  
Pszemol
 
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"Sam Goldwasser" wrote in message ...
"Pszemol" writes:

What are the common voltage outputs from the power supply ?
I am repairing my first VCR with power supply issue and
cannot figure out what should I expect in good working one.

I see 21V and -7V and many other pins with 0V.


No such thing as "common voltages". What's the make and model?


Sure, it is Zenth VRM4150.
Any schematic available for this one or similar model ?
Or any other VCR for that reason to just get an idea what to look for ?

And, as someone else shouted, do take care around the power supply.


You guys are right, and I am carefull. I have experience with voltages.
Do not worry, but thanks for worrying anyway - it was nice of you :-)


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Sam Goldwasser
 
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"Pszemol" writes:

"Ricky from trailerparkboys" rplpefkipe@kpo[fg,net wrote in message ...
Without experience you should`nt touch the powersupply, ESPECIALLY WHEN
PLUGGED IN could be 120 volts AC(ALTERNATING CURRENT) coming out
(DANGEROUS).


Relax tiger... I know what the high voltages are, I worked with TV sets already.
There you have much more things to worry about than some stinking 120V ;-)


Of course keep in mind that a self respecting switcher will have 300 VDC
in it somewhere.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
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Important: Anything sent to the email address in the message header above is
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Pszemol
 
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"Sam Goldwasser" wrote in message ...
Of course keep in mind that a self respecting switcher will have 300 VDC
in it somewhere.


Sure... but this one in the Zenith is not a self respecting one ;-)
The main capacitor is rated for 200V.
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Sam Goldwasser
 
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"Pszemol" writes:

"Sam Goldwasser" wrote in message ...
Of course keep in mind that a self respecting switcher will have 300 VDC
in it somewhere.


Sure... but this one in the Zenith is not a self respecting one ;-)
The main capacitor is rated for 200V.


Yep, no doubler. The 150 VDC or so on that cap can still be lethal though.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
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Pszemol
 
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"Sam Goldwasser" wrote in message ...
Yep, no doubler. The 150 VDC or so on that cap can still be lethal though.


Do you know this Zenith VCR ? Any info on voltages at the power supply output ?

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html


I tried to search for VCR and power supply and could not find anything in FAQ.
What is the correct keyword set to get any info about this subject ?
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Michael Black
 
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"Pszemol" ) writes:
"Sam Goldwasser" wrote in message ...
Yep, no doubler. The 150 VDC or so on that cap can still be lethal though.


Do you know this Zenith VCR ? Any info on voltages at the power supply output ?

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html


I tried to search for VCR and power supply and could not find anything in FAQ.
What is the correct keyword set to get any info about this subject ?


You go to the repairfaq page, and look through the table of contents.
There is one about VCR's and there is one about switching supplies, I think
using the complete term "switch mode".

Michael



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Franc Zabkar
 
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On Thu, 18 Aug 2005 15:04:34 -0500, "Pszemol" put
finger to keyboard and composed:

What are the common voltage outputs from the power supply ?
I am repairing my first VCR with power supply issue and
cannot figure out what should I expect in good working one.

I see 21V and -7V and many other pins with 0V.


At the very least you must have +5V for the standby logic. You should
find it on the front PCB and/or on one of the three (?) pins of the
remote sensor.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.
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Pszemol
 
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"Franc Zabkar" wrote in message ...
On Thu, 18 Aug 2005 15:04:34 -0500, "Pszemol" put
finger to keyboard and composed:

What are the common voltage outputs from the power supply ?
I am repairing my first VCR with power supply issue and
cannot figure out what should I expect in good working one.

I see 21V and -7V and many other pins with 0V.


At the very least you must have +5V for the standby logic. You should
find it on the front PCB and/or on one of the three (?) pins of the
remote sensor.


Very good point! And even this one is not existing...
So it looks like the pwr supply itself is the problem, not the short on mb pcb.
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Pszemol
 
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"Michael Black" wrote in message ...
I tried to search for VCR and power supply and could not find anything in FAQ.
What is the correct keyword set to get any info about this subject ?


You go to the repairfaq page, and look through the table of contents.
There is one about VCR's and there is one about switching supplies,
I think using the complete term "switch mode".


Thanks, I have found an example schematic the
http://repairfaq.ece.drexel.edu/sam/vcrps.pdf
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Sam Goldwasser
 
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Franc Zabkar writes:

On Thu, 18 Aug 2005 15:04:34 -0500, "Pszemol" put
finger to keyboard and composed:

What are the common voltage outputs from the power supply ?
I am repairing my first VCR with power supply issue and
cannot figure out what should I expect in good working one.

I see 21V and -7V and many other pins with 0V.


At the very least you must have +5V for the standby logic. You should
find it on the front PCB and/or on one of the three (?) pins of the
remote sensor.


There may not be a +5.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.
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Franc Zabkar
 
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On 23 Aug 2005 17:42:45 -0400, Sam Goldwasser
put finger to keyboard and composed:

Franc Zabkar writes:

On Thu, 18 Aug 2005 15:04:34 -0500, "Pszemol" put
finger to keyboard and composed:

What are the common voltage outputs from the power supply ?
I am repairing my first VCR with power supply issue and
cannot figure out what should I expect in good working one.

I see 21V and -7V and many other pins with 0V.


At the very least you must have +5V for the standby logic. You should
find it on the front PCB and/or on one of the three (?) pins of the
remote sensor.


There may not be a +5.


That's all I ever remember seeing. What other voltages are commonly
used?


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.


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Sam Goldwasser
 
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Franc Zabkar writes:

On 23 Aug 2005 17:42:45 -0400, Sam Goldwasser
put finger to keyboard and composed:

Franc Zabkar writes:

On Thu, 18 Aug 2005 15:04:34 -0500, "Pszemol" put
finger to keyboard and composed:

What are the common voltage outputs from the power supply ?
I am repairing my first VCR with power supply issue and
cannot figure out what should I expect in good working one.

I see 21V and -7V and many other pins with 0V.

At the very least you must have +5V for the standby logic. You should
find it on the front PCB and/or on one of the three (?) pins of the
remote sensor.


There may not be a +5.


That's all I ever remember seeing. What other voltages are commonly
used?


I don't know what's common but there really isn't any requirement for
specifically 5 VDC in a VCR. It's not TTL. I seem to recall that the
typical Panasonic power supplies had something slightly off like 5.1 or 5.2
But no reason it can't be 6 V something else.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.
  #17   Report Post  
 
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Franc Zabkar wrote:
There may not be a +5.

That's all I ever remember seeing. What other voltages are commonly
used?


There should be at least something between 5 and 8 volts or something
between 12 and 16 volts on most VCR's.

---
Met vriendelijke groet,

Maarten Bakker.
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