Thanks for the correction, I have not seen a 25Z6 powered set in years and there is indeed a strong "family resemblance" , especially with the pattern of holes approximately in the area where the 25Z6s would have been.

jr

Think about it logically...Back in the days of monochrome sets being more common than color 'bright spot' suppression on power off was often lacking, and customers often listened to their sets after deflection failure resulting in horizontal line burns (not to mention possible ion burns). All of that was common back then, and not all of that is easy to check for when accepting rebuilds, but it will make the finished product unsellable (especially if they handle enough of the CRT type that clients are not necessarily getting 'their' CRT back). It is relatively cheap to rephosphor monochrome CRTs (compared to color CRTs). So something that would fix those issues would be a money maker. Once color CRTs that are mostly not able to be economically rephosphored became the most common rebuild jobs the monochrome rephosphoring stations likely became a waste of space.

Makes sense! The only rebuilder operations that I remember seeing were doing mostly color CRTs at the time and had no phosphor deposition facilities. They could however, re-bond the safety shield on color CRTs, (another time consuming, tricky process).

jr

It goes to the yoke socket for the picture tube. This is Sams 126-5, same as yours.

I have to say that the quality of this set compared to others I've worked on of this era isn't anything to write home about. Cheap parts, crappy sloppy wiring.

What pin #? ... Perhaps we can reverse engineer the resistor connections and figure out what they were trying to accomplish. :scratch2:

jr

Man, you're good :)

Goes to pin 4.

Found it! looks like it is R-64 (not used on all models) 30K/5Watt that is shown below the audio output transformer. It makes connection to the +25Volt source *instead* of a direct wire. It appears to me that the resistor and focus coil and the audio output stage form a crude divider network. The focus is actually set by the pot R-2 that varies the current drawn by the audio output tube.... Good Grief!!!

jr

It's almost sounding like they took an engineer who designed some of the 7" electrostats and said "hey, wanna work on a big one?"

Me thinks this set was very much designed to a price point. The only thing that concerns me is the added cap on the v. linearity. I'm reasonably sure I traced out the disconnected caps correctly by the schematic. There's quite a few sloppy solder joints in this set, but I've cleaned them up and traced them out and they appear to be right.

There's even a factory 4 section filter can where only 3 sections of it were used. The 4th is just empty. I've only seen that on really cheap off brands. They must have sold these sets at Woolworth's or something :D

As I started to do the filter caps, I moved over one of the corroded resistors and a big chunk of the ceramic flaked off. Time to place a Mouser order.

Couple of quick chassis shots.....

All Emerson products were built to a price point! They seemed to be "third tier", competing with Olympic, Tele Tone and a lot of the private labels.
The engineer that designed the 7" e-stat, must've been rather sharp, as they were the only one to build a set to run on 110 vdc. All the other's had to have voltage doublers and tripplers.

There's definetely a resemblance to the wiring in my model 698. It's like a monkey pile of wiring, components buried at lower levels.
Not fun to work on. :no:

http://i452.photobucket.com/albums/q...g?t=1391497540

Looking at the picture in my Sams (page 16), it appears that there is a cap connected to the end of R-7... it is standing nearly on end, and identified in the picture on page 9 as C-45. C-45 is shown as a .05/400 volt cap that is connected between the wiper of the brightness control and the minus 185 Volt supply. Since the vertical lin control also connects to the -185 Volt supply, perhaps it is being used as a tie point for the -185 Volt line. If that is true, then it is not clear *why* that point is also tied to R-64 in the focus divider. :scratch2:
I would think that some careful tracing out of the connections related to the -185Volt supply might be necessary at this point in time, as it is not clear that schematic that we are looking at (Sams) represents the wiring observed in the chassis. How does the Sams compare to the factory schematic or Ryders in this area?

jr

Both those chassis, especially Tim's, have that 'prototype that has been half re-made a few times' look to them. It is surprising they did not try to clean up the chassis layout before putting them into production.

Everything I've looked at between the Sams and the Emerson schematic has been identical.

With what I've seen and traced out, my only thought at this point is to continue the recapping and hope for the best once done.