I fired up the signal generator after replacing the paper and electrolytic capacitors. It works...well, after a fashion. When I connect it to my frequency counters, I get output on AM modulated signals only up to about 1 kc. I should be able to get AM signals on higher frequencies for sure.
So I took some voltage readings and some of them were pretty far off. I decided to start testing the mica caps to see if any of them were bad. Usually, they are very reliable - even after 60 years - but you never know.
Here's the tester I have to test capacitor leakage. When we say "leakage," we mean the capacitor lets DC pass when it should be blocked. Hence the term "leakage."
I have this Heathkit IM-11 Capacitor Checker. It will measure the value of a cap, as well as test for leakage at voltages up to 600 volts DC. In the leakage setting, you flip a switch to charge the capacitor. There's an eye tube at the top, and if the cap is good, the eye stays open, or closes and then opens quickly. If the cap is bad, the eye closes and stays closed. Just what we need to test these micas in the Hickok 288X.
One end of the capacitor being tested has to be disconnected from the circuit. Caps can't be tested while they're in the circuit.
On the left is one of the caps under test. A lot of these old micas look like dominoes. The dots are a color code indicating their value, voltage rating and tolerance (in this case 100pf, 500v, 10%).
The red and black alligator clips are from the IM-11. The resistor up in the air on the hemostat was also disconnected - it went to the same point in the circuit as one end of the capacitor. I like to use hemostats as a heat sink on old resistors - they are sensitive to heat and I don't like to expose them to the full heat from soldering if I can avoid it.
Ve fleep zee sweetch and....the eye tube stays closed. This cap is bad and will need to be replaced.
So far I've tested six micas and two are bad - a high percentage for these.
(You can count on 100% of paper caps being bad).
A couple of notes on this picture.
The red arrow is the new mica in place. I reused the old 'spaghetti' insulation on one end, and put new shrink insulation on the other (see the black 'hose' looking insulation).
The green arrow shows the connector - here it's a tube pin - that the resistor and cap connect to. And this brings me to one of my pet old radio, amp, electronics gear peeves.
A lot of "restorers" will simply snip old leads from components and then use a piece of the old lead to "quig" or "clip" a new component lead to. For example, in the picture, see the old connection at the yellow arrow. Some folks might cut that lead and connect a new component to it, or just wrap a new lead around the old connection and solder away. That, to me, is sloppy, lazy, careless work. Not to mention it's a much less reliable connection.
What I do is use solder wick to remove all the old solder, take the old leads off, and then attach the new (and old, in some cases such as this one) leads to the nice, cleaned up connector. See how the new cap and old resistor leads go to the connector, have a proper bend, and are ready to solder. All cleaned up and all new solder. It's much easier to work with the connector also when it's clean - easy to insert leads.
I read this debate a lot on old radio forums, and to me, not cleaning up the old connection is simply nonsense. Folks have said "it's slow, and I have customers." Seriously? If I were a customer, I'd rather know it was done right rather than done sloppily. It takes just a few minutes to do it right. And in a way, it's also a homage to the people who wired this old gear in the first place. They put it together with care - we should service it with the same care.
Ok, rant over. Back to testing capacitors!
Since today is leap day (29 Feb), I want to make sure I post something for posterity since this day only happens once every 4 years. Here we have it.
I plugged the Hickok into my variac and brought it up gradually to 120 volts. What happened was it lit up, nothing smoked, and it was drawing under half an amp of current, so there were no shorts.
I also had it connected up to one of the frequency counters and got absolutely nothing. So I'm going to recap it and see where it goes.
I wanted to at least get an idea of where it was at, e.g. did it actually work or not.
One thing I discovered almost right away was that the output pot is frozen. The knob was turning on the shaft, but the pot itself wasn't doing anything. So that could be an issue, you think?
Here we have the old pot off the generator - it's a garden variety 10K linear. Fortunately I have a bunch of these on hand for pedal and geetar amp buildin' so I can just grab one and solder it in.
Isn't having a stash of parts a good thing? You bet it is! I hate waiting for parts to come in the mail so I tend to order a few extras now and then.
One other thing I discovered is that a previous owner connected a dial lamp to the pilot light connections and then stuck the lamp behind the frequency readout window.
Now, this is not a bad idea, and it was such a clean job I thought it was done at the factory in Cleveland. But the plastic insulation gave it away - the rest of the generator is wired with cloth insulation.
Here's the business end of the lamp wiring. As I say, not a bad idea in theory, but in practice, it's not so good.
The frequency dial is black plastic, and the light really can't shine through it at all.
So rather than leave it, I took it out.
But you do see whoever did it did a tidy job.
Now I replaced all the paper caps and the electrolytics. Here are the filter caps. I left the original can cap in place, but disconnected. I put a vintage terminal strip on the chassis and used that as tie points for the new filters.
One of the new caps I also put it is visible in this picture - it's the yellow one.
Hickok was good to put a bunch of the paper caps in a 'bank' on one side of the chassis. This made it very easy to replace them with modern caps.
It looks a little funny because the modern caps are so much smaller than the old wax/paper caps.
To give you an idea of the size difference, here's an old cap .025 uF rated at 400 volts compared to a modern one of the same value rated for 630 volts.
The old caps were dielectric paper rolled around foil. Then the whole thing was dipped in wax to try and protect it from absorbing moisture from the air. They still absorb moisture and go bad over time - the service life was probably less than 15 years. In our case, these are 60 years old and most definitely bad.
You'll hear these referred to as "wax" or "paper" caps. I think the latter is more accurate as it refers to the actual construction material.
Modern ones are sealed plastic and should have a longer service life. They also tend to be made to a higher electronic tolerance than the old ones. But they don't look anywhere near as cool.
It is possible to take the stuffing out of the old caps and insert a modern cap in them so it looks like an old cap - this is known as 'restuffing.' I've done this on special, rarer radios, but I'm not going to bother on this 288x - it's a pretty common piece of gear. I will save the old caps and keep them with it anyway.
As to the date of the signal generator, the date code on the output transformer gives us a clue. The code is "352732." We can use the list on Triode Electronics' site to
decode it.
The "352" is the manufacturer's EIA number; in this case it's Essex (Transformer Division). The "7" is the year - most likely 1947. And the "32" is the week of the year the part was produced. So the transformer dates from August 4 to 8th, 1947. So we can surmise given shipping time and perhaps time in Hickok factory stock that our 288x was built in late 1947 or early 1948.
Isn't being an electronics history detective fun? Now let's fire this puppy up and see if it works.
On Sunday I was outside, doing some painting on the long-neglected Red Pepper Fuzz while the weather was semi-cooperative.
Out of the corner of my eye I see some motion. We have a couple of neighborhood cats that meander around so I figured it was one of them. Then I looked up.
It was one of my neighbor's hens out for a stroll!
She used to have four of them, but now she has 2 "after the fox and the racoons came through." She described them as "defenseless and stupid." No wonder they let people eat them.
As I am someone who doesn't see shikkens up close very much, it was a cool experience.
She's not real afraid of people, in fact, I made some shikken noises and she came right over.
Then I grabbed her and returned her to the pen where she was reunited with her sister.
For the first time in a while, I'm going to work on something radio-related.
This is my Hickok 288X signal generator - it dates to about 1950. If you're not familiar with signal generators, what this does is output AM, FM, or audio frequencies to use when aligning and troubleshooting radios. I have an old Hallicrafters signal generator I've used for alignments in the past, but I have a handful of FM sets now and a sweep generator is needed to align them. A few years ago I snagged this to do FM alignments. I haven't even plugged it in.
I'm going to see if it woiks, and then go through it and recap it (change out all the old capacitors which go electronically leaky over time). Then I'm going to align my RF-2200.
I love old test gear, especially something like this with lots of controls.
I've seen a lot of these old generators on the web - and virtually all of them are missing the plastic cover that went over the frequency dial. Maybe it was the way they were mounted, but I don't think I've seen on with the window/cover on.
I have some thin plastic I've been saving for this project - I'll just fabricate a new one.
Taking the chassis out is easy - nine sheet metal screws hold the front panel to the cabinet. The chassis is attached to the front panel, so it all comes out as one assembly.
This was designed to be easy to service.
Hickok's stuff was 'service grade' - aimed at radio repairmen. As such, it was pretty well made and rugged. Not as high-end as say, Hewlett-Packard or Tektronix, but not consumer-grade like Heathkit.
I pull the chassis out and get a great surprise. The missing dial cover is inside the cabinet! Wow. How great is that?
The chassis on the bench.
There are two sheet metal covers over the inner works. This was done as an RF shield. There are also two access panels on each of the two boxy covers - taking them off allows access to components that would need periodic adjustment.
Well thought out, and again, made to be serviced.
Here's the chassis tipped on its side and viewed from the bottom. All of the tubes, except one, are here.
Bottom cover removed. I'll be changing all the paper capacitors in the bank of caps on the left. There's another one to the right, and one up under the meter (near the top).
The filter caps are in a can - I think I'm going to disconnect that and just put new caps on the chassis. A lot of times I'll restuff the cans, but there's plenty of room to just fit new caps on the chassis.
There's also one more capacitor inside the second, 'tuner' box.
Point-to-point wiring like this is a lost art. Look at how one lead was threaded through a terminal strip to help restrain it.
And also see the laced wiring loom on the left side. This type of wiring originated with the telephone industry and carried over into quality electronics. I have a book that outlines how to do this type of wiring.
The people who built this cared about what they were doing. Very tidy indeed.
A little history. Hickok was located in Cleveland, Ohio. They were started in the 1930s and built radio (and later TV) test gear - tube (later transistor) testers, voltmeters, signal generators, etc. The manual I have for this generator gives their address as:
Hickok Electronic Instrument Company
10514 Dupont Avenue
Cleveland 8, Ohio
I was curious to see if the building still existed, so I went to the interwebs.
Indeed it does! This is the Google street view. The building is on a corner of two streets - about 5 blocks from Lake Erie in Cleveland. If you click on the image, you can clearly see the street number on the building (I left the image large for clarity).
And, the company is still in business as
Hickok, Inc.. In looking at the pictures, the building is not as large as I would have expected. Maybe they had a larger facility and downsized? At any rate, it's interesting to see where my 288X was built!
Now that the '1940' Martin is cleaned up and ready to play, I scooped up the other two and dashed outside to get some shots of all three. It was cold so I didn't want to have them outside for too long.
Here's the Martin Triplets together. (The Three Martin Tenors?)
On the left is the circa 1950, and on the right is the circa 1940 - freshly cleaned up and ready to party.
The circa 1929 Martin is in the middle.
Now that I've worked on three of them, and am playing them, here are some observations:
The body shape of the oldest one appears to be a bit narrower in the upper bout. I'll have to measure to confirm. The lower bout appears to be a bit more squat on the ca. 1950 model than the other two.
The top color on the 1940 is lighter, but I suspect it's simply because it's been played so much more, and the top has been exposed to light and has worn off. The top color is much closer to that of unfinished mahogany. The back and sides are a darker color like the other two.
All three have 12 frets to the body. Later models have 14 frets. It's not documented when that change happened - but it may have been in the late 1950s or even in the 1960s. We do know that Martin changed the interior stamp in 1962, adding "Made in USA." Naturally, none of these instruments have that stamp since they are all older. (A 14 fret model is on my short list). The fret marker dots are very small on the oldest ukulele. They're larger on the other two.
The headstock shapes are all slightly different. The oldest one has a noticeably smaller headstock, and the top curves and point aren't as dramatic as the later models.
There is about a 1/2 inch height difference in the point between the 1940 and 1950 models.
And the older ukulele also doesn't have the Martin decal - it's stamped on the back of the headstock.
The bridge pins appear to be ebony on the older one, and appear to be plastic on the two later models. The bridges are all identical, and all of the saddles are ivory.
How do they sound? They all sound great, but each has its own voice. I should record them all to try and demonstrate. It's a little hard to judge because they all have different types of strings, but overall, this is how I'd describe them:
The ca. 1929 is the most resonant hands down. It's the most 'alive' when you play it - the top and back really vibrate. I'm glad I fixed the back crack, because the back is a big part of the sound on this one. It has that crisp clear Martin tone on the treble strings. It sounds pretty fat on the bass too, but that's mainly because I have it tuned to low G with a wound G and C string. I haven't touched the action at all, and it plays well as is.
The ca. 1940 actually sounds a tad 'drier' than the other two - this could be due to the Worth clear strings I have on it now. But it is very resonant also and sounds very balanced. The action is on the high side at the saddle and the nut - I am going to shave some height off the saddle and deepen the nut slots a bit.
The ca. 1950 is the one I'm most comfortable playing in terms of its action - I did set it up and it plays very well. It's got a full, barky tone, and the treble is crystal clear. It doesn't quite have the 'live' feel of the other two - it's in super clean shape and I suspect it hasn't been played as much. (Although I did have it on the shaker for about 80 hours to open it up some).
I'm fortunate to have three of them to compare, and am looking forward to playing them more. Now back to practice!
Now on to the frets. They are very heavily worn, and I'm going to do the best I can with a level-and-crown on the frets.
My guess is that I'll still have some divots, but I can at least make them smaller. If it plays ok afterward, I'll leave it. I could refret it, but I'd prefer to leave the original frets on it if at all possible.
Here we have the frets after a few passes with 180 grit paper on my corian leveler. I had marked the fret tops with blue marker and then leveled 'em. The remaining marks are divots. I was about halfway through when the picture above was taken.
I'm going to leave it here. There are some divots on the first four frets - where the wear was the worst - but they are a lot shallower.
I could have kept going, but a few of them are so deep they're within a millimeter or so of the fretboard. I don't want to sand them that low.
Now we crown the fret tops with a crowning file. The fret tops were flat after the levelling, so a crown needs to be put back on.
The divots also got cleaned up a little more during the crowning. I'm thinking it will play just fine. Since the strings are nylon, they shouldn't hang up in the divots like steel strings would.
A little filing with a fret end file rounds the ends and takes out any sharp edges. I'm using a Stew-Mac fret protector. These things are gold. Easier than using tape to protect the fingerboard.
I used the Dunlop fingerboard conditioner, then a few drops of this lemon oil.
Not just any lemon oil...Ultimate Lemon Oil!
Cleaned, levelled, crowned, conditioned and oiled.
I was concerned about the depth of the finger divots on the lower frets. They actually look worse in this picture than the are. They're somewhat deep, but they don't affect playability at all. I actually think they give it a great vibe. It's been played, which is what it was made for.
Where did that dirt on the upper bout go?
Reinstalling the tuners.
You can see how good the finish looks in these pictures. It cleaned up very well.
I strung it up with some Worth clears - high G this time. All three of the Martins have different strings on them - a good chance to try them out and compare.
One thing I like about the Worths is you get enough length in the package to cut two sets.
When we left our circa 1940 Martin ukulele, it was on the workbench about to get a bath. A big bath. Enough to clean off 70 years of dirt and grime.
I took the tuners off so I could clean them up and polish them. It will also be easier to clean the headstock with them off. Always hard to get around those sting posts.
A cleaned up tuner on the right, and a dirty (Unclean? Sounds Biblical.) tuner on the left.
I used a weak mixture of Simple Green to get some of the dirt off, then polished with Mother's Wheel Polish. Good stuff.
Also polished the knobs with Novus #2 plastic polish.
Glad I took them off, it was a lot easier to worth with them not being on the uku.
I used Kramer's Best Blemish Clarifier followed by Kramer's Antique Improver.
I may not have mentioned this, but this thing was really filthy. I'm guessing it was played a lot, the original owner (the seller's grandfather) passed away, and then it sat parked for a while.
It took numerous - as in 7 or 8 passes with the Clarifier to get the dirt off. This picture shows some of the dirt - this after like 3 or 4 passes - that was coming off. Changed rags a number of times.
But the upside is you can also see how good it's starting to look! I can't recommend Kramer's stuff enough. It's all natural and works wonders.
You may recall heavy black marks on the heel. All gone. Banished from the Martin ukulele kingdom!
If you thought my old Martin's frets were disgusting, that was nothing. Look at all the crud I scraped off. Ugh. Gross.
I made 7 or 8 passes with the Dunlop fretboard cleaner. The board was almost black before - now it looks like rosewood again.
I know, right? Crazy.
Here we have another Martin tenor ukulele on the bench! (This makes three). Turns out these things are like peanuts. You can't stop buying them.
Well, this is the last one of the bunch for now. And if I keep buying them I won't have any money left in my car fund, so there is a (temporary) hiatus.
Anyway, on to the work I did on this one. This one's history is that it was bought pre-World War II. As hard as it is to exactly date Martin ukuleles, I think that seems reasonably accurate given the features. Since I have 3 to compare, I've been making notes on some seemingly minor but important details. More on that to come.
One thing is clear: this one has been played - a lot.
There are two spots on the top where the finish is gone. One is the left side lower bout where the player's arm would contact the top. The finish is gone entirely from a fairly large area. There is also a lot of ground-in dirt there too - visible in the pictures.
The dirt should clean up I believe.
The second spot of missing finish is on the upper right bout - it's a smaller area where the player's right hand would finish on the follow-through of a strum.
There is also a lot of dirt near the neck on the left upper bout. A lot of play wear - I love it. If I can clean it up, this should be a real nice played-and-loved looking instrument.
The back is in fine shape. Ironically, given how much this one has been played, there are a lot fewer scratches than my 1929 Martin. And no cracks or other issues at all to fix on the body.
The finish on the back looks a lot brighter in color than the top - a testament to how dirty the top is.
A lot of finish wear on the back of the neck near the headstock. Most of the finish seems to be gone, in fact.
And more dirt on the heel.
Here's the really crazy wear. Years and years of grunge on the frets. If you thought the green junk on my old one was bad, that was nothing compared to this.
There is also a lot of fretboard wear on the first four frets - and a lot of fret wear too! I've never seen anything like this on a nylon string instrument.
I think what happened is as the fingerboard began to wear, the strings were pulled down more onto the frets, and the first few frets began to wear. And as grooves were worn in the those frets, the strings then began to ride lower onto the upper frets - to the point where the upper frets began to show the same wear.
It really needs to be refretted, but I'm going to do a level and crown first and see how it plays. I really don't want to mess it unless I have to.
This thing must have been played constantly! It's really remarkable.
A couple of nights ago I had the great privilege to see the amazing Peter Frampton on his "Frampton Comes Alive 35" Tour. I was also fortunate to snap a few pixtures during the show. This is a tour begun in 2011 in honor of the 35th anniversary of the famous "Frampton Comes Alive" double album, originally released in 1976.
The guy is pretty amazing. It's clear he's having a great time, and he just burns on the geetar. I was astounded by his stamina.
When I was growing up, the original Frampton Comes Alive record was everywhere - it got huge radio play, everybody had a copy, etc.
He played a whole bunch of guitars during the show:
- Newer Gibson Les Paul sunburst
- Newer Les Paul Custom
- An old, beat up Les Paul Custom :-)
- Gibson ES-335 - cherry, block markers
- Early 60s SG Les Paul with inlaid ebony tailblock (he's had this since his Humble Pie days)
- Red Fender Strat, white guard, maple board
- Gibson acoustic - looked to be "D" size - not slope-shoulder - with "The Gibson" on the head.
- Dreadnaught-style acoustic - brand unknown.
- Martin D-42 (I believe, likely the Frampton model?)
- Koaloha soprano ukulele (with a Planet Waves tuner clipped to the head)
Here he is with "the" guitar - his famous, iconic 1954 Gibson Les Paul Custom pictured on the cover of FCA (and elsewhere...). This is the guitar that went down in a cargo plane crash in Curaçao in 1980 and was recently recovered. Here's
more on the story.
As an aside, 1954 was the first year Gibson offered the LP Custom model.
He's having a good time, don't you think?
He played the entire FCA album in its entirety, then played another set of his newer material. If you get a chance to see him, I highly recommend it. He's a fantastic player and a class act.
One of the last tunes he did was a tune called "Vaudeville Nanna and the Banjolele." He played the opening on his Koaloha soprano uku. I realized after I got home and looked at the pictures that I have the same clip-on tuner too! (It's a little Planet Waves model).
Coming down the home stretch. I need to clean the fingerboard, and then put some Kramer's on the body, string it up and twang!
There was a lot of dirt, crud, buildup on the frets. Actually along the sides of the frets. I took an X-Acto knife to this stuff to free most of it up. Ugh.
I had just read on the interwebs about this Dunlop fingerboard cleaner and conditioner. Since I have instruments that could use it, I got some.
The cleaner rocks. I don't know what's in it, but it removed all the grime from the ukulele's fingerboard. I made a few passes - until a cloth stopped turning brown.
After the cleaning, I used some of the conditioner. The fingerboard looks amazing now.
Final step was to polish the frets with these "fret erasers" from Stew-Mac. I had been using fine steel wool, but wanted to give these a shot.
They work great at removing file marks (I didn't have them but I'm sure I will on some other instrument) and really polish the frets up nicely.
The fingerboard cleaned up, conditioned and frets cleaned. It's gone from being black to its original color.
As an aside, this is Brazilian rosewood. Martin used this on their instruments until the late 1960s when the export ban went into effect in Brazil. At that time they switched to Indian rosewood.
I used
Kramer's Best Blemish Clarifier and Antique Improver on the body. These are two different products - the clarifier cleans up haze, seems to magically minimize the appearance of scratches, and just works wonders. The Improver puts a nice gloss on the finish, and according to the Kramer's people, replenishes natural oils in the wood.
I've used their products for years and they are absolutely wonderful.
The back of the uku looks much better now. You can see the repaired crack - it's visible, but it's solid.
The wear marks on the front look better after the Kramer's was put on. The finish was pretty dirty too - now it's clean, had a nice gloss. It looks like an old but cared for instrument. A real relic (as opposed to those fake 'relics' that are prevalent today).
The beautiful rosewood bridge and ivory saddle.
I strung it up with this set of low G Aquila 'Bionylon' strings. I got them because they have a wound 3rd and 4th string, which I wanted to try.
Now I have 2 ukuleles tuned to low G - this one and my Kanile'a. I needed a low G tuning for one of these classes I'm in - it's a sight-reading class using James Hill's books. A lot of the parts are written for low G. At first I wasn't sure, but now I dig that tuning.
Apparently I am being 'green' by using these strings.
