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Philco 38-690 electronics restoration. - Printable Version

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Philco 38-690 electronics restoration. - morzh - 04-12-2017

Just to start the thread.

Tonight I put the tuner chassis on the bench.
It is missing the bottom cover. I know it should have one as 37-116 does and they are very similar.
I do have an extra 37-116 chassis and if it has the cover abd it fits, I'll use it.

The chassis is dusty but not rusty/dirty
The dial seems to be in good shape. All tube and shields are present; the test will show if I need any new tubes.
It seems the chassis is lighter than the 37-116; I wonder if it is due to the output stage being separate.

Photos later, Saturday.

RE: Philco 38-690 electronics restoration. - Radioroslyn - 04-12-2017

Power transformer is down on the bottom chassis too isn't it?

RE: Philco 38-690 electronics restoration. - Ron Ramirez - 04-13-2017

(04-12-2017, 08:19 PM)morzh Wrote:  It is missing the bottom cover. I know it should have one as 37-116 does and they are very similar.
I do have an extra 37-116 chassis and if it has the cover abd it fits, I'll use it.

It won't fit. The 38-690 tuner chassis is smaller than the 37/38-116 chassis.

I've never seen a cover on a 38-690 tuner chassis. It doesn't really need one as it sits on a wood shelf. On the other hand, the 37-116 chassis only rests on front and back supports, and so most of the chassis is exposed at the bottom, hence the chassis bottom cover.

RE: Philco 38-690 electronics restoration. - morzh - 04-13-2017

Terry

Does look like it. Another reason for the chassis to be lighter. It helps - the chassis is barely manageable when it has the transformer. On the other hand, the bottom one is much smaller and despite the two transformers will be much easier to turn around.


Ron

thanks, you put my mind to rest. I was wondering about it and thought the cover might be there for EMI reasons, though other Philcos do not have them, but then who know how a complex chassis behaves. So the cover was there mainly for the safety so no one sticks their fingers inside when it is open.

I take it, then 38-116 does not have the cover either? It is also inclined and rests on a full board.

RE: Philco 38-690 electronics restoration. - Ron Ramirez - 04-13-2017

I don't think the 38-116 does, but it has been quite a while since I owned or serviced a 38-116 and I honestly do not remember. Since it also rests upon a shelf and the bottom is not exposed, I would be frankly surprised if it did have a bottom cover.

And, yes, the bottom cover was put on the 37-116 chassis for safety reasons.

RE: Philco 38-690 electronics restoration. - morzh - 04-15-2017

Initial Photos

I think when I purchased this one about 1-1/2 years ago I put out the photos of the cabinet and the chassis, so I won't repeat myself and will start with the photos I took yesterday when I put it on the bench.

   
   
   
   
   

RE: Philco 38-690 electronics restoration. - morzh - 04-15-2017

.....and the reason the Chassis lacks the power transformers is because it is (well, they are) here:

   

RE: Philco 38-690 electronics restoration. - morzh - 04-15-2017

First time....all 21 tubes are good. One 6J5 is a bit low but still good.
Both 5X4 are strong and 6L6 too which was a surprise.

RE: Philco 38-690 electronics restoration. - Kenneth F. Besso Jr. - 04-15-2017

OH my,, that tuff sub chassis,,,,WOW,,,God Bless YOU,,,,Patient's

RE: Philco 38-690 electronics restoration. - morzh - 04-15-2017

Well,

I have just cleaned the top of the chassis and sometbing looked a bit off.
Then I realized someone painted the chassis with silver paint. With a brush at that. My doubts were confirmed by a light wire running along the suface that also got a coat of paint.
Ok, not the biggest worry.

The RF chassis upon a closer look seems pretty benign compared to the 37-116. No buried caps and lots of space. No need to take it off unless there's something wrong with the switch.

Just one backelite cap block. The rest is tubulars.
Plus two tubular electrolytics, seem like factory or authorized service-soldered.
The aluminum cap on top is dual Aerovox, so not original.

The sch quality sucks in NA.
I have been using their prints so far. Maybe it's time to try Chuck's product.

RE: Philco 38-690 electronics restoration. - Ron Ramirez - 04-16-2017

Mike (morzh)

Do not, do not, DO NOT bother that bakelite block! It does not have a capacitor inside. Instead, it contains the coils for the set's 10 kc filter. Leave it alone.

RE: Philco 38-690 electronics restoration. - morzh - 04-16-2017

Ron,


Thanks for warning! I was surprised myself about a single backelite out​ of so many caps.
What probably could avert the disaster is my habit of first finding the part in the assembly dwg and then in the sch and looking to what to replace it with before gutting (exception is made for tubular caps) but still I could make that near fatal mistake.

Thanks again! Even better, no messy job.

RE: Philco 38-690 electronics restoration. - morzh - 04-16-2017

The recap started today.
Restuffed some tubulars.
I decided to try polyester caps for 8uF ones as they readily fit instead of the 8uF lytics.
The can will be restuffed; though not original, still looks better than a hole with newer can soldered underneath.

RE: Philco 38-690 electronics restoration. - WallaceRoger - 04-16-2017

That is one gorgeous set. I'm looking forward to seeing the end result!

RE: Philco 38-690 electronics restoration. - morzh - 04-17-2017

It will look decent: the cabinet is not in bad shape and can be left the way it is with some GoJo cleaning; unless Kirk will come to me and beg me to let him restore it Icon_lol