The two Sentinals
 

I picked up two Sentinal 7" electrostatic sets from ebay. One a model 400 and the other a IU400. Both use 7JP4s. I've read all the horror stories about the electrostatic sets and am prepaired for the danger. So far I took the model 400 apart. I have never seen a set come apart so easy. There are two chassis; an audio/video chassis and the CRT chassis containing all the HV caps, the CRT, etc. This set seems to have a power transformer on the AV chassis. The power switch/volume control is on the same chassis and connected that way. It also has a stinky selenium rectifier in the AV chassis which are red. The CRT chassis has two blue stinky selenium rectifiers. Looks to me like the power transformer handles everything, as the power rating on the set is 175W and the power transformer looks big enough.

I plan on fully recapping it and replacing the selenium rectifiers, and getting some nice AST HV caps. This set definately looks like it had repair work done before. 3 out of 4 of the HV caps were changed. The AV chassis really doesn't have as much tubes as a 630TS chassis. How well do these sets work and how good is their picture? And does anyone else have any last minute advice? :)

Chuck,

From doing a search I saw that you have one. How do you like it?

Thanks.

Jonathan

Jonathan,

I think the quality of picture on just about all the 7JP4 sets is conditioned on how good the CRT is. The Sentinal sets are pretty easy to work on, I don't remember any "gotcha's" when I worked on them. I bought my 400 because it came from an old collector who probably bought it from the original owner while it was still in operation, 40 years ago.

Chuck

I have one that plays good, but the CRT is weak. Tunes in stations just fine and the pic is pretty stable... just a bit faded due to the tired 7JP4.

Last night I took apart the IU400 Sentinal. It's pretty much identical other than the way the CRT is mounted. I can't wait to get the service manuals and parts so I can try bringing these sets back to life. I'll make sure to keep you guys posted on my progress.

Thanks.

Jonathan

For the people who have these sets, (400 and IU400) does anyone know what kind of service data is available. I couldn't find anything on samswebsite. It uses two chasses and I tried the CRT chassis. The CRT chassis in the 400 is the 20E374A, and the CRT chassis in the IU400 is the 20E374.

Thanks.

Jonathan

Jonathan:

The Sentinel 400-TV 7" Portable is covered in Sams 73-11.

Tim,

I cannot thank you enough! :)

Jonathan