1967 Executive 972 opinions? Updates on restoration.

[grindfix]

Where is that picture from? Too much room to be the sub. Have to tell the rest of the story...

 

[larryderouin]

I'm standing between the tubes in the After room, next to the remote gyro angle repeater at the Aft bulkhead. Here's the full pic. No room for my shoulders between the tubes so I'm standing offset. One of the crew is shining brass on the tubes. (gotta give officers brats something to do.......)

 

[grindfix]

You look very focused. Or concerned. Or both
Looks like a screenshot from the movie. Great shot for an avatar!

 

[nsgn007]

so yours is the 31R chassis and has the FM hum also? ...mine is the exact same ... I have not had the time to take mine out on the bench , but I did sub those 6CW4 nuvistors just on a whim... it did not make a difference ... I was hoping for one to be shorted .... I think some DC is getting though the FM section somewhere ... first thing I would do is check all the power supplies to the FM. as I tune in a station the hum gets louder... could be DC getting into the multiplex as well... too bad there is no option to shut off the MPX to see...

 

[grindfix]

In last few years of working on electronics, mostly on solid state stuff, I found out that it's not worth the effort (some may argue but...) trying to pinpoint the reason of malfunction until all 50-60 year old electrolytics are replaced. Then, if problem is still there, I go over and look for the culprit, which is usually direct result of a capacitor damage due to age or over-voltage resulted from higher AC input from the outlet. In my experience, about 50% of time wholesale electrolytic replacement takes care of hum and other noises so I plan to start there. Parts should arrive tomorrow. I have Pioneer SA-9900 on the bench first, then Fisher. BTW, I was impressed to see that Ampex plays in both directions. In my old world that option was not available until about 1985. Consumer electronics were not important to our government.

I'll let you know if electrolytic refresh will take care of this FM hum.

 

[KentTeffeteller]

Very Nice score Dimitri! That AMPEX is a very good Tape Deck. Although I wish they had come out with the GLASS Heads instead of AKAI. But there are places that will lap heads or replace them still out there. But it's very $$$$$$$$$$.

Ampex deep gap heads outlast Akai GX heads in real life. Facts.

 

[fred soop]

DTG110B. I think Germanium. I don't see any bias pots there or removed. Schematic does not shows pots either. My unit is serial #14xxx something

I don't have the schematic but it's probably similar to a 440-T receiver. Possibly the pots were only on units with 4 transistors per channel. There was a service bulletin to modify many of these units to eliminate the pots. If you don't have the pots, that will save you some trouble.

 

[grindfix]

This receiver has a lot of small transistors inserted into sockets. I can easily see oxidized transistor legs cause connection issues. I will be testing and treating all of them with deoxit before unit is powered next time.

 

[nsgn007]

At least yours has the R2R... my regent did not have one... and being the window seat model the clearances for a R2R are ridiculous ... the console had to be designed around the R2R .... I mean only 6 inches clearance for the overall height so the lid will shut? how many R2R do you know that are less than 6 inches in height?

 

[grindfix]

How do I choose (C69 / C70) safety capacitors to replace those death caps? Originals are 600v rated, probably what they had at that time.

 

[larryderouin]

0.1uf x/y rated for 300v AC.

 

[grindfix]

0.1uf x/y rated for 300v AC.

I don't see that identification in Mouser selection. What are they calling them?

 

[larryderouin]

I looked in my stash, and found my pile of Safety caps.

Mouser part #81-DE2F3KY103MA3BM2F 0.1uf 250VAC 22,097 in stock. $0.78ea. 10 for $5.75.
Murata Ceramic Disc cap
https://www.mouser.com/ProductDetai...CJezauimSaffCIs4MLK4phDsnuxd2PhupNNrj7/UX8%2B

 

[grindfix]

So all "Safety Capacitors" with appropriate rating would work, right? They just don't designate X/Y in the description, which doesn't help to search. Only in the datasheet

 

[larryderouin]

Type in [ 0.1uf 300vac X1/Y2 Safety Capacitor ] . You'll get the option of Ceramic or Films. And 151 different ones to boot.

 

[grindfix]

Do you have any suggestions for dial lights here?

https://audiokarma.org/forums/index...ong-festoon-bulb-source.929603/#post-14115924

 

[grindfix]

All electrolitycs replaced along with 4 film caps in the preamp section. Death caps on order. All controls cleaned and lubed. Small transistor sockets deoxit treated. Drivers and outputs were marked, removed, cleaned and re-greased. I attempted to test those Germaniums but quickly realized that they can't be reliably tested with DMM. Knowing that unit produced output before removal from the console, I powered it up on DBT. So far - success! No weird noises, no hum and great sound with floor standing 8ohm test speakers. FM hum is gone! Happy!



Most of caps I used were radials and I soldered them with handshake to original capacitor leads. This helped eliminating flimsy construction. Several caps that were located near chassis wall got attached using Marine Adhesive. It's a really strong, sticky, non-acidic silicone. Works great for securing capacitors.

Few minor issues to track down:
Tuning meter does not move in FM. Works in AM just fine. Some testing to do.
Headphone jack is MONO and second channel wire is dangling around the area. Maybe it was a Stereo socket originally but something other then headphones was inserted and broke one of the prongs? Kid stuck a pencil in?
Dial bulbs... 51mm long. I can get away with making extension caps to slide over caps on 41mm LED bulbs, but if I go LED, I want to try Green. I got them for my 400 but I can't remember where I got those. If anyone knows - please let me know.
Below: L-R 400 bulb, Executive bulb, 41mm Warm White LED with add-on caps, ...

 

[fred soop]

You CAN test the germanium transistors with an analog meter.

 

[grindfix]

Not with digital though, correct? I don’t have functional analog meter.
Several vt meters I couldn’t get them to work right, asked a friend to take a look. I think they are on his back burner list.

 

[gadget73]

think you want 0.01uf safety caps, not 0.1. Thats the original value, and would offer a lot more impedance to a 60hz 120v line. Less current on the chassis.