Anyone interested in new "stock style" PC boards for the Dynaco FM-1 & FM-3?

Bill Thomas · « **on:** 6 Jun 2009, 08:41 pm »

I am "toying" with the idea of having new Printed Circuit Boards made for the Dynaco FM-3 tuners. Anyone have any interest in a set? As anyone who has tried to rebuild one of these tuners knows, the original boards are EXTREMELY fragile and don't usually survive a total rebuild of the tuner. Traces lift, break or crack WAY too easily. The Phenolic substrate on two of the boards tends to char and crack, and even the RF board doesn't fare too well when you try to rebuild it.

Yes, I am aware that Chauncey (over at the FM-3 zone) offers a "tuner on a Motherboard" solution, I am talking about replacement boards in "stock configuration." This would allow people to rebuild defective "sections" of the tuner, rather than make them rebuild the entire thing. When you just want one repaired, rather than rebuilt, it *could* be a cost-saving solution.

Artwork is currently ready for production and I will be etching a set of boards tonight to see how they turn out, but if there is enough interest, it would be possible to have a board manufacturer turn out more "cosmetically appealing" boards.

Let me know what you think.

Sincerely,

Bill Thomas

smbrown · « **Reply #1 on:** 7 Jun 2009, 12:01 pm »

Bill, sure, I'd be very interested!

Bill Thomas · « **Reply #2 on:** 7 Jun 2009, 07:01 pm »

Just a bit of an update here. I *should* have a complete set of boards etched by tomorrow. There may still be some cutting and drilling left, but we *should* know by tomorrow IF the artwork is correct and if the boards will be suitable for a production run.

I'll be posting more as soon as I *know* more.

Thanks,

Bill Thomas

Cure · « **Reply #3 on:** 8 Jun 2009, 10:44 pm »

Anything that keeps the Dynaco tube tuners going without cannibalizing other ones is a great idea. People will need help with diagnosing what needs to be replaced, though.
Keep up the good work.
Matthew Perks

Bill Thomas · « **Reply #4 on:** 9 Jun 2009, 09:35 pm »

Well! There has been a LOT of activity since Yesterday. After several "false starts" (and several boards that simply didn't work out properly), I *finally* have something to share with everyone - especially Matthew!

I should digress for a few moments. Matthew is *probably* the most PATIENT person the world has ever known. I have had a tuner of his for, well - nearly FOREVER now. It all started with a dead quad cap, and then degenerated from there. After replacing the capacitor, Matthew got a few hours of use out of the tuner, whereupon it simply drifted and died. Back it came for further evaluation and repair. As it turns out, I discovered an *incredibly* tiny break in an RF circuit board trace. (I'd display a photo, but it simply is not visible.) This turned into one of those "intermittent" problems that would "come and go" with TERRIBLE irregularity, but I *finally* discovered it after WEEKS of searching and benching; benching and more searching. Then another drift problem popped up. Checked EVERY resistor and capacitor and wound up replacing a few resistors, but it took several cans of "component cooler" to find a capacitor that *seemed* to cause some drift "issues." Still, I was not *completely* convinced. Another couple of rounds of benching and testing ensued. All *appeared* to be fine until I went to put the covers back on. After everything was assembled again and I was listening with *some* satisfaction, I barely "touched" the tuning capacitor and it shifted. Upon closer inspection, it turned out the tuning capacitor was not going to be reliable. MORE repair, another tuning capacitor and more testing and alignment, followed by further testing. Then, while flexing the tuner *slightly* while it was playing, ANOTHER *intermittent* problem showed up.

As it turns out, the Printed Circuit boards in Matthew's tuner are not in the best of condition. That brings us to the issue of new circuit boards. (And that's where we are today.)

Here's a picture of a "stock" Dynaco PC-12 multiplex board:

(This is not the board from Matthew's tuner.) Not much has been done to this particular board and it *appears* to be fairly intact. If I were to attempt to strip the parts, there is little doubt that MANY of the circuit traces would lift off the phenolic substrate. (Two other boards I was attempting to "reclaim" wound up with MULTIPLE trace problems.) Only one solution left - let's make a new board! Here's a picture of the "rough draft" version of the multiplex board:

While not cosmetically *perfect*, this board is completely capable of replacing an original bad board. There were a few rough "corrections" to the board prior to etching, but the artwork is actually *almost* ready for a final pass at a new board. (There are a couple of "painted in" pads on this particular board and some of the numbers for the different connection points and test points are missing. They will be corrected before the next attempt at etching another board.) Notice that this board has not yet been drilled for component mounting.

Now, here's a picture of the PC-7 RF board:

This is also in "un-drilled" condition, but again, this would be a fully functional board in an FM-3. (The scratches you see are actually just slight surface scratches. They would disappear with further cleanup. The sunlight makes them appear more pronounced.) This board's artwork is actually complete and satisfactory for production.

Throughout this entire saga, I have been wracking my brain trying to discover exactly WHY there should be so many *seemingly* unrelated problems happening with this tuner. The answer *appears* to be due to a previous "upgrade and repair" job that was done some time back.

Matthew previously had someone do a "restoration" on this tuner, and had the "Berning Mods" installed. While it wasn't *immediately* apparent, it looks like the overall culprit is silver-bearing solder. During the previous restoration, every solder joint was re-heated and a *bit* of silver-bearing solder was added to the joints. The trouble is, it takes quite a bit more heat to make a good silver-bearing solder joint. And since very little of the original solder was removed, the actual "mix" of solder at each connection varies quite a bit. Some joints are mostly silver-solder in nature. Others are mostly tin-lead solder. While I can't be totally CERTAIN, it *appears* that this is the cause of MANY unrelated problems with this tuner.

So Matthew has become a bit of an "unwilling guinea pig" in this grand experiment. I am TOTALLY committed to return a reliable unit to him. A tuner that will perform as close to a new unit as humanly possible. I had originally planned to salvage circuit boards from other "donors" I have available, but the circuit boards have not been co-operating. After two multiplex boards "went South", it was time to go a different route. And THAT, my friends, is where we are today.

Matthew's tuner has been working "off and on" for a LONG time now, but the reliability factor has been WAY below acceptable levels. Tonight, will provide another "run" of RF and Multiplex boards, AND I "hope" to be able to show the results of the first PC-8 IF strip board as well.

Matthew, don't lose hope *quite* yet. You WILL have a reliable tuner back "in the case" in VERY short order.

Whew! Lots going on, but this is a VERY important topic for ANY of us who treasure the beautiful music a Dynaco FM-3 tuner can provide. Anyone have any other comments to add? Feel free!

Sincerely,

Bill Thomas

Bill Thomas · « **Reply #5 on:** 12 Jun 2009, 06:05 pm »

June 12th, 2009 - Update: "I Have a Drill Press, and I'm Not Afraid to USE It!"

There has been a great deal of progress since my last report. Our PC-7 RF board is ready to populate with components. (There has been a lot MORE progress, but let's just follow things along "one board at a time.")

Here's a picture of our NEW PC-7 RF board for the FM-1 and FM-3 tuners.

After MUCH careful checking and re-checking of the hole positions, the board has been completely drilled, filed and is ready for assembly. I'll post another update when the board has been completely assembled and is ready to install in the chassis.

Meanwhile, our PC-12 multiplex board is *almost* ready to "stuff" as well. Once we finish the construction details of the PC-7 board, I'll cover the multiplex board next.

Sincerely,

Bill Thomas

Bill Thomas · « **Reply #6 on:** 17 Jun 2009, 09:52 pm »

June 17th, 2009 - Update: "Time keeps on slipping, slipping, slipping... into the future!"

(Thank you, Steve Miller)

At LONG last, our NEW PC-8MX circuit board is ready for "Prime Time." Here's a picture:

This new PC board is FR4 fiberglas and should handle the heat of an FM-3 MUCH better than the original phenolic board material.

Meanwhile, our PC-7 RF board has been "stuffed" with parts and is ready to install into the chassis. Here's a picture of the result:

Other than the coils and a few (now) impossible to find capacitors, the rest of the parts are all brand new. This should allow us to construct a tuner that will have a second lifetime of use available.

More to come!

Sincerely,

Bill Thomas

Hank · « **Reply #7 on:** 26 Jun 2009, 11:33 am »

Interesting, Bill. I have my original AM/FM version in the closet (I think the model was AF6). It's been years since I used it and I think the AM was not working. Anyone offer service on these? I don't have equipment for tuner troubleshooting/tweaking. I do have my original H.H. Scott LK-48B tube integrated amp that I will re-cap, as well as three similar factory-built versions I've bought off eBay, and two Scott tube tuners. All waiting for more spare time (maybe when I retire in 3 years). Keep up the good work!

Crawfish · « **Reply #8 on:** 17 Feb 2010, 04:21 pm »

Hi Bill -

I've just finished reading through all of your FM-3 threads. Absolutely amazing work!

I have a few FM-3s in the queue to work on. I'd be very interested in sets of the boards if you're still offering them.

-Kevin

Hank · « **Reply #9 on:** 19 Feb 2010, 12:42 pm »

Has anyone re-furbed and/or tweaked an AF-6?
thx

Bill Thomas · « **Reply #10 on:** 19 Feb 2010, 04:01 pm »

Hi, Hank!

I have only one AF-6 in my "Dynaco Stash." I haven't powered it up since I received it, so its condition is 'unknown" at this point. At present, I don't have any plans to restore it just yet because there is a LOT of other equipment "waiting in the wings," but I'll add it to "The List" for a future rebuild. It'll *probably* be a few months before I can get around to a complete restoration on it.

Sincerely,

Bill Thomas

baldrick · « **Reply #11 on:** 19 Feb 2010, 04:22 pm »

Quote from: Bill Thomas on 17 Jun 2009, 09:52 pm

Meanwhile, our PC-7 RF board has been "stuffed" with parts and is ready to install into the chassis. Here's a picture of the result:

Bill, how did you manage to install L1 since your PCB does not have plated-through holes?
L1's leads are "blocked" by its plastic frame - the assembly manual instructs you to solder it from the top for that reason.

Bill Thomas · « **Reply #12 on:** 19 Feb 2010, 04:48 pm »

It was tricky. I pre-tinned both the circuit traces and the wire leads, then soldered both wires with a *tiny* bit of space between the board and the coil form's surface. Then, I applied heat to both wires from the reverse side of the board and gradually seated the coil until it was flat against the circuit board. This is one of the reasons that I referred to the boards as "still in prototype stage."

I *should* have the ability to make plated-through holes when the "circuit board line" is completely functional, but I have never produced plated-through holes before, so this is a bit of a "learning experience" for me as well. I'm not a total stranger to the plating process, but this is the first time I have been "on my own" with a plating project. I plan to cover it in a future series of "updates" when the details have been successfully conquered. (I also hope to be able to print the correct "component guide" to the top of each board, but that has yet to be completely worked out.)

Much to do and not anywhere NEAR enough time to do it all, but I WILL keep everyone posted. Right now, I'm concentrating on the current preamp "project" before I make any future promises. All I can say at this point is "it'll be 'interesting' when all the dust settles."

Bill

baddog1946 · « **Reply #13 on:** 30 Jan 2011, 02:24 pm »

Hi Bill;
How can I buy the circuit boards for the FM3 from you?
thanks
Please respond to
Geomcgolrick@yahoo.com

dmag · « **Reply #14 on:** 31 Jan 2011, 10:46 pm »

Bill ,
I am absolutely interested . I have 2 FM3's in my basement.
They're the missing link in my Dynaco system.

Steve

tagliumato · « **Reply #15 on:** 28 Feb 2011, 08:55 pm »

Hello eveyone !
Are these boards still available ?

stewdan · « **Reply #16 on:** 24 May 2011, 05:07 pm »

Hi Bill,

Are your circuit boards for the FM3 still available for purchase???

If so, how do I go about obtaining a set?

Please let me know,
Stew

denny9167 · « **Reply #17 on:** 25 May 2011, 10:16 pm »

Quote from: stewdan on 24 May 2011, 05:07 pm

Hi Bill,

Are your circuit boards for the FM3 still available for purchase???

If so, how do I go about obtaining a set?

Please let me know,
Stew

I have a full set fully populated that are available for purchase. Just PM me.

Thanks

Denny

stewdan · « **Reply #18 on:** 26 May 2011, 07:14 pm »

Hi Denny --

I am a new member to this forum and could not find a way to PM you.
(Privaledges issue??) When I clicked on your name or Bill Thomas' name I got an error message about not being able to view any profile???

Anyway I am definitely interested in a set of the FM3 boards. I see that you said populated boards. Are there other flavors of the boards available?

Can you send me a message thru My Messages? I see that I can get to that.

Awaiting your reply,
Stew

michael_nipomo · « **Reply #19 on:** 17 Dec 2011, 08:45 pm »

Hello,
Have watched your amazing work on the FM3!! Have been spending all my time working on upgrades to the PAS & PAM and have gotten behind on your work on the FM3. But, just today, saw your most recent introduction of PCB's for the FM3. Are they available and if so for what price?
Regards,'
Michael