[TV MAN]

Well, it's been sitting on my bench taking up space and it's time to get it up and running. Abay find. Wasn't expensive. Found 2 actually, but one is missing most tubes, etc and looks like might have taken a lightning hit at some point, so for the most part - it's parts. The one I'm reviving is complete with all the tubes, so I brought it up on a dim bulb and much to my surprise, it worked! Not stellar, but I could get some stations. I ran it long enough to learn it doesn't drift and the filter can gets pretty warm. I also learned that it had been dropped or something and the whole chassis was bent around the power trans and the tuner didn't work the best. I straightened the chassis best I could and then the tuner wouldn't work like it should. There's a shaft inside a shaft, where the inside shaft is hooked to the tuning knob and the outside shaft is connected to the dial. The two didn't interact anymore! Some of the ball bearings were coming out of the end of the shaft on the tuner too, so I did a swap, since the tuner on the parts chassis seemed to work. Got that swapped last night and it worked, but wasn't very sensitive. I did some light adjusting on the tuner screws and improved it a lot, but the stations are off and not sure how to align those. I don't have much experience aligning tuners, so I stopped there until I can get some info.

The next thing was to redo the filter can to avoid either a ka-boom or that magic smoke. Since I didn't happen to have a suitable can laying around and really didn't want to spend $50 ordering one, I did the individual caps. Probably not the prettiest thing but it's not for looks either, and it worked. So - got that done and it works pretty good overall, but think it could use an alignment touch up. I also need to test tubes to make sure I don't have any weak ones messing up things. Looks like it's got some hours on it but don't see evidence of much tinkering other than finding some "Groove Tubes" in those shields. 

I included a picture of the knobs - they are quite dull. Does anyone know a way to brighten up those to look better? Something to soak them in maybe?

   
   
   
   
   

[TV MAN]

Here's a pic of my can job and it playing on the bench. There are some pics of the can replacement. Take a look at the last pic - there are some white square caps, I don't know if original or if those are newer, but debating on if I should leave 'em alone or replace. Any thoughts?

   
   
   

[morzh]

If you mean the two pieces on the left and a couple on the right, larg yellow boxes, they probably are film caps and probably are good.

What you could do is to see if it has any indication of the mfr and the series number that would indicate what cap it is, and try to search for the datasheet.


As for the tuner alignment, if you mean the FM one, it should be very similar to any other FM alignment. Running bare non-modulated carrier or IF 10.7MHz and aligning the discriminator output etc, and then aligning the tuning trimmers, whatever type they are.

[TV MAN]

I really don't see any evidence that those caps have been replaced. The parts unit has those brown dip caps, so I suspect this is a later production. So far, the biggest problem I see is the dial is off and I don't see any mechanical adjustment. It's a little difficult to tune for a clear signal, so I suspect the alignment should bring it back in. I'll try shooting that 10.7 signal in and see how it responds. Done plenty of AM alignments but never done an FM alignment.

[morzh]

I've done one and it was very recently, with that Zenith backelitre radio. Finished it in the beginning of this year. You could look it up, to see what challenges I encountered.
I do not have an FM oscillator, but with the procedure they described I did not need any modulated signal, so my regular HP generator was sufficient.


https://philcoradio.com/phorum/showthrea...nith+7H920

[MrFixr55]

Hi TV Man, 

Would love to have seen the "Parts Chassis".  One had a lightning hit, the one you are working on appears to have lung cancer.  I think this one smoked 2 packs of Camels per day.

I found the assembly, operating and alignment instructions for the kit version of this set, but it is too big to attach to the post (about 8 MB).  Send me a PM w/ your e-mail address and I will e-mail you a copy.  However, to get you started, here is the schematic and the complete alignment instructions.  No test equipment is needed other than a digital FM radio to confirm frequency of the stations selected during the alignment to "rock in" the tuning dial accuracy.

Dyna FM3 Schematic.pdf Size: 446.89 KB  Downloads: 113

Dyna FM3 Align.pdf Size: 1.31 MB  Downloads: 119

For most sets, the trimmer caps on the main tuning cap are what are used to rock in the dial accuracy, and on most tuning caps, the frontmost section is the oscillator. Note that on your set the oscillator section does not have a trimmer. On your unit, set the tuner to a station high on the scale and adjust C8 for accuracy. then select a station on the lower end if the dial and use L4 to calibrate. go back and forth between these 2 settings to "rock it in". They likely will then tell you to adjust the RF and mixer trimmers on th cap for max strength. All measurements are made with the tuning eye.

Re the knobs, start with a good Windex bath.  Front panel too. I find that to take off tobacco residue very well.  However, it does not work well on the person who smoked enough in that room to stain that set as much as it is.

Hope this helps, and works.  I own a Dyna PAS-3X (or should I say that my Brother now owns it) and a Mark 4 "monoblock".  Dyna makes very good products.

[TV MAN]

Thanks guys! I'm still working with this, but running into a couple issues that you might have already been through. I followed the instructions - mostly - ... I started with the IF as described in the instructions. All tubes tested good, exc the GT 12AX7, which I replaced. Showed partial short when warm. That aside, I tuned between stations and listened to the hiss like the instructions said, then touched up the alignment. The bottom slugs on T2 and T1 seemed to really bring it in.

Now - here's where I stopped and need a little advice. When I tune in a station, I have to detune it slightly to get it to come in - meaning, if the eye tube is fully closed, it is about half muted and no stereo indication. If I slightly detune, then it comes in clearer and the stereo indicator comes on.

Next - the discriminator. I haven't touched it yet, instructions say to detune the top slug and adj the bottom slug, but step 24 on the alignment says to tune a station to peak, check the #31 voltage for -11. Reading on, you set for zero. Ok, so I just did a check - with the tuning eye fully closed, it's off. Way off. But - if I detune the station for best reception, then it zeros. So - when they say tune the station for peak, are they meaning clearest signal - or peak eye closing? I think that's where I'm a little confused. If it's peak eye closing - the station kinda mutes, so - adj the coil for zero there? Or, should I redo the IF alignment?

Things just seemed a little off before I started, so is the reason I'm checking this. I truly suspect the Disc trans is off a little, but need a little help before going further,

Edit: I see that lung cancer! I think both are about the same. I suspect the original owner is long deceased. +1 on the quality of the Dynas! Dynaco was my 1st "good" tube setup, found a Pas2x and ST70 in a used stereo store when I was a teenager, and when I got it hooked up and heard how it sounded, I put away my Akai solid state separates and never looked back! In fact, I still use my Pas 2x, and my 70 still comes on and sounds great! My favs tho are with my Mk 3s.

[morzh]

Wow, Tim, you are juggling quite a few project at the same time. I cannot bring myself to do one.

[TV MAN]

Too many Mike! Too many. I jump from one to the other. Then back. Oh, you haven't seen the garage yet - redoing an engine that failed a lifter, then camshaft! Oh, not to mention the recent kitchen & bathroom remodel! I feel guilty if I sit for a spell!

[morzh]

I have just seen a short on the Youtube; a woman says she feels irate whenever she sees her husband relaxing.
It seems that you don't need no one to tell you "hey why are you sitting here doing nothin' ?"

[radiorich]

Hello Tim,
you sound like me I am currently juggling 4 projects not counting mine !!
I had 5 but I put one to rest .
Sincerely Richard

[TV MAN]

I think we try to do too much as we age and things can be a mess at times! I believe I have the alignment in check as it tunes and plays very well. Very sensitive - except ... well, ya know there has to be something ... a beloved intermittent! It loses signal strength when it warms up, which can be "fixed" by twisting the chassis, or sometimes wiggling the RF amp tube, but not always. Oh, forget pushing things with a screwdriver handle or something. I thought I had it when I tightened screws around the tuner board,, nope. Played for several hours, put the case back on, played beautifully, sat down with a big stupid grin with a sense of accomplishment,  then went down within 10 minutes, so it's back on the bench after cleaning up some newly fragmented papers. Gonna reflow solder connections, look for cracked trace, clean tube sockets and check grounds. Maybe this is why the chassis was bent down in the middle??? Figured it was abused in shipping, but when I straightened it, the tuner shaft stopped turning correctly, and now this ... huh... kinda reminds me of a Goldstar TV with a similar problem that finally left the shop with a piece of styrofoam wedged under the chassis 

So I did get the knobs cleaned up beautifully. I dropped them in the Ultrasonic for about 20 minutes, then scrubbed with a toothbrush, then another 10 minutes. 

   

[radiorich]

Hello Tim,
Wow, that Dynaco FM-3 turned out beautifully! I’m really glad I bought my ultrasonic cleaner years ago—it came from a jewelry shop. I’m thinking about getting a bigger one to handle larger items. Most of the time, I use Dawn as the cleaner, but I’ve never tried Simple Green. What did you use?

Sincerely Richard

[TV MAN]

Thanks Rich! I do in fact use Simple Green. It turned out better than expected. I have a bigger ultrasonic and mainly use it to clean carburetors on small engines. It's inexpensive and works pretty good. Thanks for the links Mr. Fix! With the intermittent, I've been thinking about swapping tuner boards - ya know, a little cheating, but after looking more closely at things, I suspect it wasn't lightning, they probably had the same problem and bridged traces. I hope that's the problem. The more I work with it, the more it seems like a "sudden shift" in frequency. Not much, just enough to move the station a little off freq. I can affect it by spraying with chiller, but can't quite pinpoint it. I can touch the osc coil and bring it in - and what I mean isn't moving the coil, but the inductance (or capacitance) of my finger. I've soldered quite a few suspicious connections, but after about 5 minutes or so, still goes off. I'm going to next pull the board and check for any dirty grounds, even though it's grounded through the tuner to the chassis via a soldered wire. I really hope it's not silver mica disease!  Anyway, today is a 'rain day', so I'm going to take another crack at it.

Edit: I wanted to add that Simple Green works good for removing smoke stains and such.

[TV MAN]

Well, I believe I found the culprit and it wasn't what I thought. It wasn't even on the tuner board, after spending almost all the evening reflowing connections, I ended up finding the problem area on the IF board near the detector coil. I suspect they had problems previously, and how I missed the clue is beyond me. Notice the pencil glued to a capacitor and a bunch of glue all over? Yeah - a clue. So I found that only after warming up for about 5-10 minutes the signal would drop out accompanied by static. I originally thought it was drifting in the tuner area, but watching the tuning eye carefully realized the signal was fine, it was losing strength after the IF, dropping out of stereo and dropping the volume level. 

   

I found that I could push the detector coil (T5-small pic right beside the level control) with my finger - only after it got hot - and bring the signal back. I could even hear each stereo channel come in or drop out depending on how much I flexed the can. So - I resoldered the connections to the can. What happened?? I lost my signal level and couldn't get it back in at all. So - I hoped for a bad connection inside the can. Nope. Next I pulled the can from my parts radio - and, Oooh great... it's an 'Automatic'. Ya know, the SMD kind, right? What do I have to lose? I popped the can in and powered it on - it played ok. Not perfect, but good enough to test things and found the problem solved. I did an alignment of the coil and brought things in really nice.
   
     

So, as of right now, I believe the problem was the connections to one or both of the wafer caps in the base of the can. I suspect this has been an issue before judging from the hob-cob repair in the picture, but it adds personality, so it stays. I'll cook it for awhile and see if it holds. So far, it's been playing for over an hour with all the covers on.