A portable Beta VCR from 1985 works perfectly except there is no color:

1. Pre-recorded color tapes play back in B&W
2. Tapes recorded on this VCR play back in B&W on this VCR
3. Tapes recorded on this VCR play back in B&W on other known good VCRs

Therefore, the VCR can neither record nor playback color signals. What
is the most likely cause?

Is it the 3.58 MHz oscillator, the comb filter, the color killer, or
lack of a color burst? Or, is it just a defective transistor or IC that
contains an internal B&W/color switch?

Thanks

"VCR Gymnast" wrote in message
oups.com...
A portable Beta VCR from 1985 works perfectly except there is no color:

1. Pre-recorded color tapes play back in B&W
2. Tapes recorded on this VCR play back in B&W on this VCR
3. Tapes recorded on this VCR play back in B&W on other known good VCRs

Therefore, the VCR can neither record nor playback color signals. What
is the most likely cause?

Is it the 3.58 MHz oscillator, the comb filter, the color killer, or
lack of a color burst? Or, is it just a defective transistor or IC that
contains an internal B&W/color switch?

Thanks


My guess would be the 600kHz3.58MHz conversion circuits. Do u have a
schemo for this unit and what kind of test signals are u capable of
injecting?

VCR Gymnast ha escrito:

A portable Beta VCR from 1985 works perfectly except there is no color:

1. Pre-recorded color tapes play back in B&W
2. Tapes recorded on this VCR play back in B&W on this VCR
3. Tapes recorded on this VCR play back in B&W on other known good VCRs

Therefore, the VCR can neither record nor playback color signals. What
is the most likely cause?

Is it the 3.58 MHz oscillator, the comb filter, the color killer, or
lack of a color burst? Or, is it just a defective transistor or IC that
contains an internal B&W/color switch?

Thanks

Today I fixed a sony vhs with this symptom. e-e pic ok, tapes no
colour, as you describe. had to resolder a bit in the y/c section and
replaced several 1uF caps and the 4.43 xtal for good measure.
-B.

"VCR Gymnast" wrote in news:1152157251.328327.300970
@a14g2000cwb.googlegroups.com:

A portable Beta VCR from 1985 works perfectly except there is no color:

1. Pre-recorded color tapes play back in B&W
2. Tapes recorded on this VCR play back in B&W on this VCR
3. Tapes recorded on this VCR play back in B&W on other known good VCRs

Therefore, the VCR can neither record nor playback color signals. What
is the most likely cause?

Is it the 3.58 MHz oscillator, the comb filter, the color killer, or
lack of a color burst? Or, is it just a defective transistor or IC that
contains an internal B&W/color switch?

Thanks


Have you tried cleaning the heads? We had one that went to black and
white and cleaning the heads made it come back to color part way.

Puckdropper
--
Wise is the man who attempts to answer his question before asking it.

To email me directly, send a message to puckdropper (at) fastmail.fm

VCR Gymnast wrote:
A portable Beta VCR from 1985 works perfectly except there is no
color:

1. Pre-recorded color tapes play back in B&W
2. Tapes recorded on this VCR play back in B&W on this VCR
3. Tapes recorded on this VCR play back in B&W on other known good
VCRs

Therefore, the VCR can neither record nor playback color signals. What
is the most likely cause?

Is it the 3.58 MHz oscillator, the comb filter, the color killer, or
lack of a color burst? Or, is it just a defective transistor or IC
that contains an internal B&W/color switch?

Thanks

Make sure there isn't a color / bw switch somewhere, like on the back panel.
Seen it on U-Matics, anyway...

Mark Z.

Puckdropper wrote:
"VCR Gymnast" wrote in news:1152157251.328327.300970
@a14g2000cwb.googlegroups.com:

A portable Beta VCR from 1985 works perfectly except there is no color:

1. Pre-recorded color tapes play back in B&W
2. Tapes recorded on this VCR play back in B&W on this VCR
3. Tapes recorded on this VCR play back in B&W on other known good VCRs

Therefore, the VCR can neither record nor playback color signals. What
is the most likely cause?

Is it the 3.58 MHz oscillator, the comb filter, the color killer, or
lack of a color burst? Or, is it just a defective transistor or IC that
contains an internal B&W/color switch?

Thanks


Have you tried cleaning the heads? We had one that went to black and
white and cleaning the heads made it come back to color part way.

I cleaned the heads both manually and with a Scotch cassette cleaner,
but no improvement. Video remains B&W.


Puckdropper
--
Wise is the man who attempts to answer his question before asking it.

To email me directly, send a message to puckdropper (at) fastmail.fm

Mark D. Zacharias wrote:
VCR Gymnast wrote:
A portable Beta VCR from 1985 works perfectly except there is no
color:

1. Pre-recorded color tapes play back in B&W
2. Tapes recorded on this VCR play back in B&W on this VCR
3. Tapes recorded on this VCR play back in B&W on other known good
VCRs

Therefore, the VCR can neither record nor playback color signals. What
is the most likely cause?

Is it the 3.58 MHz oscillator, the comb filter, the color killer, or
lack of a color burst? Or, is it just a defective transistor or IC
that contains an internal B&W/color switch?

Thanks

Make sure there isn't a color / bw switch somewhere, like on the back panel.
Seen it on U-Matics, anyway...

There is no external BW/Color switch. This switch is present inside an
IC somewhere in the chroma circuit, which is a separate module in this
very small modular VCR. Even though this VCR is a Beta from 1985, it is
the smallest VCR ever made.


Mark Z.