I have a hickok 539c model that tests all 6BE6 and 12AU7s as weak that test just fine in the sylvania 140.

Maybe it was just my tester as AFAIK it was stock having never been worked on.

I always phone in Mouser orders and request USPS First Class on small orders that will obviously be 13 Oz or less. Typical charge is under $3. A 1 pound Priority Mail package is less than UPS and above that UPS is cheaper from TX to NH. A penny saved etc......

The .7A is quite low if I remember the spec, look at the manual.

Carl

Yeah I've been thinking of putting together a test jig of some sort to test out the ammeter part of the wp-29b. The 180A makes it hit 0.5A

I think I have one of those old wall plugs that converts directly to a light socket.
I'll figure up the voltage watts etc to find out how many amps.
In fact I think there's an online calculator to save the longhand math.

As Carl stated, USPS charges are very reasonable on small orders and Mouser doesn't inflate the shipping cost. Some suppliers add significant handling fees to discourage small orders but that is not Mouser's practice.

I have gotten lazy and just order online now but the order staff at Mouser was excellent whenever I used the 800 line. At least in the past the order staff received commission on the order placed and they provided great service (pointing out when you were near a quantity discount break point, providing alternative items for products not currently in stock). Obviously they were bored at times because one time when I placed an order to stock up on hookup wire the service representative commented that I was choosing really boring colors

I assume that this service level did not change when they became part of the Berkshire Hathaway (think Warren Buffett) family of companies.

Rodger WQ9E

The manual (Y2K-R3) says 140W with the ovens off. That's about 1.2A .

Dave Wise

Yeah, I figured it was time to look into the ammeter circuit on the wp-29b

Today I removed everything from the radio. Front, back, and side panels of the chassis to where it was just panels only.
Lots of oil everywhere, especially where the chassis panels/assemblies meet.

I filled up some 5 gallon buckets of hot soapy water and gave chassis panels a wash and rinse.
Every single chassis panel mating surface, screw/thread, screw hole got cleaned with de-oxit and buffed out, and put back together.
I like ground continuity

The area of the chassis where the power supply mates to has a little corrosion.

I'll leave a bare chassis with front and back panel until the sub assemblies can be looked at further.

The RF deck turned out to be a capehart too.

The antenna relay assembly is a black tarnished mess.

Something curious was the multi cap plugin cans (30 & 45uF) were replaced with ALL 33uF.

All that oil.... Looking in the light the bottom dust cover has a whole area where it looks to be wet with oil too

If you cant align or hammer something into place use plenty of oil. Works great on gear trains until they get all gummed up with dirt.

Carl

Added a couple photos of the dismantled cleaned chassis, the RF module, and a couple pics of wires/resistors that look like they got too hot at the connection, or were poorly soldered, heating the insulation too much towards the end of this album https://www.facebook.com/media/set/?set ... 6511cf894c

Starting with this pic https://www.facebook.com/photo.php?fbid ... 4c&theater

The level you guys bring these things down to, and then back up to, is simply amazing to me. I visited a gentleman yesterday here in the Minneapolis area to purchase a freq. counter, and got the royal tour of his place in the process. This gentleman has NO LESS than fifteen 8-foot tall racks in his basement that are COMPLETELY filled from floor to ceiling with these historic Collins systems, and every one is in complete/refurbished/close to mint working order! Kid you not, he must have 30, 40, 50, or more of these monsters down there! He takes them COMPLETELY apart, rebuilds 'em, and puts them back together. When I say completely, I mean COMPLETELY! The pictures he's taken, with the smallest of parts - it just amazes me. Man, and that's just the beginning of what's in this guys house. There was so much high quality vintage gear in his place that it seriously freaked me out. He had a complete Navy transportable radio system (trailer transportable, that is) he is selling and getting it ready for freight shipping. Let me tell you, the truly gigantic transmitter and receiver gear that make that system up makes single Collins pieces of gear look like true midgets - there had to be at least 10 pieces in all to that system, and it had to weigh at least 1000 pounds - seriously. You guys are amazing...

The other term for it might be "obsessive compulsive"

Dang, that might be me too.

Curtis Eickerman

Is there any other way

Carl

What can I say? It seems to work for me.

Curtis Eickerman

They make meds for that, you know.

Let's just say I don't recommend them.

Are those yellow Aerovox caps originals you reckon? They are starting to unroll.

I just went to Mouser and got every single paper and electrolytic in the radio on order.
Went with 99% Vishay orange drops except for the 2uf oil on the IF deck where it was unavailable, and went with a CD instead.
I decided against the nice newly fashioned cans for the big electrolytics because I have enough dud octal tubes around where I can make my own. I went with the new(ish) pencil style 47 & 33uf caps to go on the octal bases. In fact I think I have some metal octal duds.

The main thing that swayed me away from the nice new custom cans was the price. 50 bucks, or 15 bucks for most likely the exact same caps inside. I maybe even bought better ones.

The only ones I didn't replace was the 8uf@30v, and the ones inside the line filter because I couldn't find comparable replacements.

I went with a 600V rated for the B+ blocking cap to the filters for an extra margin of safety.

About the filters. I think I may be experiencing a symptom I'd read about called "blow by" in the 4KC position.
It does it's job for the most part, 4KC wide. But it seems to be letting some very high (around 15 to 16KC?) frequencies through too.
Hmmmm.

Ok, I just re-bought all the orange drops as my first purchase was the 225P kind. I did some data chart comparison and decided there might be an advantage to the 715P temp stability.

Now that I have both the 225P (polyester) and 715P (polypropylene) paper replacements (neither have been installed yet), I'd like to hear you guys' opinions on both.
So far I'm thinking the 715P, and will sell the 225P as a kit.

Your votes?

So far as I can tell (not that I've studied them too hard) there are yellow Aerovox, and glass sealed PIOs for the papers in this radio. No BBODs.
My guess is there needed to be better paper caps (PIOs) in some places and cheaper ones (yellows) were fine in others.
My hopes are the orange drops (225P or 715P) will be equal or surpass both in original spec. Some of the old R-390A archives really get into nit-picking about the caps. I think I'd read that some of the caps had an inductance etc that may have critical and expected properties about them for a circuit to function as intended, and new caps will have the same uF rating but other properties that are different, and might throw things off.

What I'm aiming at for the paper project is to replace them and have the circuits function EXACTLY as intended with caps that are available today.
I'm not interested in hacking or modding this radio with "improvements". In fact, I'm on the lookout for a tube socket that matches the rest so I can remove the resistor and put a 3TF7 back. I might find other mods as I dig in, but so far the 3TF7 resistor swap is all I've noticed.

Your input and suggestions are appreciated.
Thanks!

An easy mod to get rid of the 3TF7 resistor is to use 12BA6s for both the PTO and BFO tubes. The fils of these tubes are wired in series thru the 3TF7. Just short the 3TF7 resistor, swap the tubes, and you're done.

Believe almost all the bypass caps were PIO originally. I wouldn't go replacing them unless you knew they were bad, or where they could cause catastrophic failure (ie blowing a mechanical filter) - they generally last a long, long time.

John provides excellent advice, with high reliability components there is a greater likelihood you will either create collateral damage or potentially introduce new faults due to poor lead dress or placement than there is of original component failure.

The one capacitor I would definitely replace with a good quality replacement is C-553. This is the capacitor that blocks DC voltage from the mechanical filter transducer coils and a failure here will destroy the mechanical filters. If you suddenly notice a selectivity position not working do NOT try the other positions because if this capacitor fails it will sequentially destroy each filter as you select it.

My R-390A was a lucky hamfest find and it came with a spare ballast tube but if both the original and spare burn out in my lifetime it will get the 12BA6 treatment as suggested by JN. My 390A was the first Collins radio I bought and it was a last minute hamfest purchase several years ago in Princeton, IL. I was heading back to my pickup to leave the fest when a car pulled up next to me and he opened his trunk and there was a R-390A inside. It had the original meters, top and bottom covers, manual, and several spare tubes. The seller told me the price was $50 firm and there was a blur as I quickly pulled out the money It was in very nice shape and turned out to be a Collins manufactured unit with all original matching modules. I replaced C-553 and then lubricated and aligned it and that was the last time I have been inside it. Next year at Princeton I found an Eldico SBA-1 sideband adapter which nicely matches the R-390A and a sealed in box RAK-7 receiver. It remains a favorite hamfest but nothing quite compares with those two years of finds

Rodger WQ9E

Feel free to replace all bad or out of tolerance parts, but make sure you install the new components EXACTLY like the component you are replacing.