Sony TV-750 - Power cord alternative?

[Thibault]

Hi all,

I just acquired a Sony TV-750 and it is my very first vintage TV!

While the seller said it was in working condition, they could not locate the power cord.

This model uses a 4-pin cable that I cannot find anywhere but after comparing it with other models, I am under the assumption that maybe:

The two top pins may be used to charge the battery while the two bottom ones may power the device.

It is also a funny coincidence that a regular two-pin power cord fits perfectly into the two bottom pins.

I am too afraid of ruining the TV or blowing a fuse at home so I did not try to power it just yet.

Can someone tell me if my assumption is correct or if i am dead wrong?
And i can indeed use a regular two pin power cord, does the orientation matter?





Thanks!

[Alex KL-1]

Congratulations!!
Seems that Sony has changed the contacts; I have a working TV-700U, and the AC connector is separate and square (is older of course).
Is possible to measure with a DMM to be sure in most cases, if is not possible to find some info about: the AC part will measure a fixed DC resistance (since is a primary of a power trafo); and the DC part will measure different, due to having capacitors and diodes/transistors in the path, measuring rising values until stabilize, and different values (on a diode scale) for a polarity than another. Trouble is, if is similar to TV-700U (it have the CRT heater direct connected to DC), the measurement is more confuse.

BWT, be prepared to replace all electros in making restoration.

My TV-700U have a great image, with plenty of bright, contrast and good sharpness (after full restoration).

[Alex KL-1]

https://www.radiomuseum.org/r/sony_tv_750tv75.html
In the rear stick on this photo (scroll until it appears), the AC seems to be on the smaller pins...

[Thibault]

Thanks for the quick response Alex!

Looks like I avoided a disaster by not trying to power it on then!

Thanks for pointing me in the right direction though. Being a complete electronic newbie I will attempt to do the measuring as you suggested (if only to learn) but beyond that, it looks like i will have to try to source on of the original power cord...

[Electronic M]

You want to be careful with those Sony power cords...They used that 4 pin arrangement on everything for years and depending on the device and age sometimes the close pair are AC and sometimes the wide pair is AC...

[Thibault]

Oh damn… thanks for the warning! I learned my lesson and will ask the sellers moving forward!

[damen]

Sams Photofact set number 1364, folder number 3, does show the AC connection pins as the smaller, closer set, top ones. If you have no interest in running the set on 12 volts you can always go in and swap the connections on that connector and use the cord you now have.

[etype2]

It looks like you have the problem solved with a suitable power cord.

I did this when in a pinch with my Sony KV 5100. I don’t recommend this unless you are careful not to short out the connection. By doing this, the clips have to be stable and will not move while testing. Also need to insulate the conductive areas and power only to verify operation, not as a permanent solution. You can see the odd receptacle on the Sony.

[Electronic M]

Originally Posted by etype2

It looks like you have the problem solved with a suitable power cord.

I did this when in a pinch with my Sony KV 5100. I don’t recommend this unless you are careful not to short out the connection. By doing this, the clips have to be stable and will not move while testing. Also need to insulate the conductive areas and power only to verify operation, not as a permanent solution. You can see the odd receptacle on the Sony.

That Sony with plug prongs in the back should have been easy to make a cord for. There were a lot of TEAC RTRs and other gear that used a cord like the AC half. And some 60s extension cords will fit too. I made a cord for my teac by taking one of those black bakelite outlets that tube recievers of the 50s and 60s had, removing the chassis mount bracket soldering a cord to the terminals and covering the terminal region with silicone...Worked great for years until I happened on a spare cord.