RCA VR653 HF power supply help needed

[k_teppo]

Hello.

This VCR is becoming a pet project of mine. With help from the group,
I was able to source the eject lever a couple of years ago. The
machine has worked without a hitch until very recently, it stopped
dead.
Previous postings regarding RCA VCR's and power supply problems
describe rectifier diodes that fail when loaded. The main filter cap
has about 160v on it. (Rectified 120v -- I'm in Canada) I think
they're OK.
I am reading zero volts at pin 11 (with reference to pin 7) on IC801.
(IC801 is U4614B) According to a schematic of another power supply
that uses this chip, pin 11 is VCC and pin 7 is GND
R818 appears to be open, but unsure of value. Red, Red, Red, Gold,
Yellow are its colours. I think that's the right order. But that
doesn't make sense according to the resistor guide I'm looking at. Can
someone please verify this resistor's value?

Thanks very much!
-k

 

[Shoreline Electronics]

Assuming your VCR is dead ( You didn't say?)

---------------------------------------------------------------
Text pasted from WinSTIPS 2.0
http://www.ServiceSoftware.com
---------------------------------------------------------------

RCA VR653HF

Dead.

A Helper Elect

Ic801 219269, R817 220607, Q801 225523, R818 2.2k, And Fuse In Power Supply.

---------------------------------------------------------------



--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
[email protected]
========================
"If you push something hard enough it will fall over."
Fudd's First Law of Opposition - Sir Sidney Fudd

 

[Jerry G.]

Over an email, it is hard to fix one of these. Check for high ESR caps.
Failing caps in the power supply is a very common cause of failure in one of
these. You can only test the caps with an ESR meter, or change them to test.
There will most likely be more than a few that are bad.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


Hello.

This VCR is becoming a pet project of mine. With help from the group,
I was able to source the eject lever a couple of years ago. The
machine has worked without a hitch until very recently, it stopped
dead.
Previous postings regarding RCA VCR's and power supply problems
describe rectifier diodes that fail when loaded. The main filter cap
has about 160v on it. (Rectified 120v -- I'm in Canada) I think
they're OK.
I am reading zero volts at pin 11 (with reference to pin 7) on IC801.
(IC801 is U4614B) According to a schematic of another power supply
that uses this chip, pin 11 is VCC and pin 7 is GND
R818 appears to be open, but unsure of value. Red, Red, Red, Gold,
Yellow are its colours. I think that's the right order. But that
doesn't make sense according to the resistor guide I'm looking at. Can
someone please verify this resistor's value?

Thanks very much!
-k

 

[k_teppo]

Over an email, it is hard to fix one of these. Check for high ESR caps.
Failing caps in the power supply is a very common cause of failure in one of
these. You can only test the caps with an ESR meter, or change them to test.
There will most likely be more than a few that are bad.

Thanks for the input Jeff and Jerry. I do have an ESR meter, so I will
be able to check out the caps. It seems to me that the problem is with
the IC itself (possibly failed from stress due to failing caps)
I jumpered in a 2.2k ohm resistor at location r818, and it failed
quite nicely. smokey! ;-)

Thanks again
-k

 

[k_teppo]

Assuming your VCR is dead ( You didn't say?)

---------------------------------------------------------------
Text pasted from WinSTIPS 2.0
http://www.ServiceSoftware.com
---------------------------------------------------------------

RCA VR653HF

Dead.

A Helper Elect

Ic801 219269, R817 220607, Q801 225523, R818 2.2k, And Fuse In Power Supply.

---------------------------------------------------------------

Hi Jeff.
Yes, this unit is dead. Fuse is (and was) OK. Q801 checks out ok. This
fact is not surprising since the fuse was OK. However R818 is open.

-k