Let the fun begin....

 

Emerson BW 231 - 1938

The Half Mae West....

My typical parts-is-parts replacement method

this is one of the easier parts to replace.

Capacitor C7

That's all, kids!

New Restoration Project - the "1/2 Mae West...." 1938 AM - Short Wave Radio

 

A recent gift - from a friend familiar with my interest in restoring old radios.

This is an Emerson model BW-231 - also known as the Half Mae West.

Emerson "1/2 Mae West"

What's the frequency Kenneth?

Emerson Logo Detail

A brush with some old-school Rock and Roll

Carl Griffin - Grammy Awards, Motown, a Jazz record label... and much more - 

bought this from Joey Dee - Peppermint Twist - in 1968.

He never played it, as it was in need of restoration. I hope to get it rocking' and rollin'!

It is a good candidate  for restoration - the circuit is a common 6 tube receiver design

that was popular for several decades - schematics and modern replacement electronic parts are available.

First Look Inside....

The primary parts to replace are the old wax, paper, and 'bumble bee' capacitors - the electrolyte

inside the originals disintegrates - turning the capacitor into something that may short,

act as a resistance, and ignite or explode, damaging other componentsthat are NOT

easy to find replacements for - e.g. transformers coils, etc.

Under the hood....

Component density isn't too annoying - this will be relatively easy to get to the parts that need replacement.

Wax caps - the four tubular tan bits....

Not sure what the two little red bits are... will need to figure that out before powering up.

Next step - I will draw diagrams and schematics, recording the values of each of the parts that are removed. There are about ten parts I will order and replace, followed by some more detailed detective work to identify any mysteries as I progress.

Stay tuned in, so to speak.

Webcor 2110 Sings Again

 

She listens, she sings.

A little Art Blakey, for her first full run in decades.

Webcor 2110 Parts Replacement and First Light

  

This Webcor 2110 reel to reel deck was an excellent candidate for a relatively easy restoration - it was in good physical condition, and nothing was missing. There was a schematic inside the case, and, of course, the world wide web is your informational friend. http://www.tapeheads.net is a great resource for anything tape related.

After the cleaning and initial evaluation, as in the previous post, I ordered and replaced the paper/wax capacitors, as well as the Bumblebees - see previous post - and one resistor that was obviously heat-stressed.

I like to keep things as 'original' in appearance as possible, although the goal is function - and this stuff is hidden from view. Still, neatness counts 😁

Component values used in old electronics are often a little different than the modern parts that are typically available. This site has a great selection of parts that match original values - https://www.tubesandmore.com

There are endless, and sometimes ridiculous discussions about capacitor choices for audio circuitry. Search away. There were some component choices that could improve the audio performance.

My take? The heads are worn - I have a decent 'hi-fi' deck - the Revox - see earlier posts - and this thing is a monophonic marvel with a frequency response in the order of 70 - 10Khz - I don't expect it to rival some hi-fi wonder. I plan on recording some vintage shows, so it is fine without extensive mods.

Here are some parts-is-parts images, and the first light-up video.

Three for One! The yellow, gummed-up thing is a multi-section capacitor, with three caps inside. There are modern versions; however, because of the odd combination of values, I will use three separate parts.

Some of the caps are hiding under a mess of other stuff, and can be somewhat annoying to replace. 

The only other type of component replaced was a toasty resistor - the middle of the body had been cooked - the three bands should be yellow, violet, and red - and measuring the value shows that it is way off - compared to...

 

...this value, which is correct.

It's ready to fire up. Ideally, I'd ramp up the voltage with a variac - 70-something year old components can be a bit unpredictable 🔥🧯🧨   😜

First function check....

Play and record, both directions, FF and REW, and the eye tube work. I still need to get some felt on the tape head pressure arms - cotton balls used to protect the forward and reverse play heads - and see if it actually handles the tape properly, and records and plays back. The heads were quite nasty looking!

Next: The reel (so to speak) test!

Webcor - Initial Electrical Evaluation

I've finished an initial cleaning of the upper mechanical tape transport circus, so I'm moving on to the electrical bits. Once the electrical bits have been revived, I'll return to the motors, springs, and levers for adjustment.

Vintage electronics, in this case from 1952, have components that don't age well - powering them up after decades of storage is not a good idea!

There are 13 wax-covered capacitors that must be replaced, as they no longer work as intended - they often can turn into resistors, short out, or have radically different values. This can cause extensive damage to other components, including fire, and shock hazards! 

🚒🧨🎆🧯💣

Don't plug these things in until a thorough evaluation and replacement have been done. There are also several old Bumble Bee capacitors - they have black bodies with a number of color coded stripes - these must be replaced as well. Other components will be checked for any signs of heat stress, cracking, or bulging.

Some of the wax paper capacitors that will be replaced....

All of the capacitors and sketchy looking parts will be located on the schematic, which was found inside the case. Then, an initial parts order will be made.

Sometimes, manufacturing changes will vary from a supplied schematic. Component values may change, parts deleted, or additional parts may appear 😃

I have worked on gear that people have 'modified' - deleting or improperly replacing parts with things that are ridiculously dangerous 💀, pointless, and some that don't do anything at all! 😂

Here's my typical secret process - been doing this for a few decades 🤓

Usually, I like to concentrate on one type of component. In this case, the capacitors. I chose the easiest one to start with 😜

This is an example of a wax paper multi-section capacitor - C14A, 14B, and 14C, three caps in one package. There are four leads - one that is common to all three sections, and then seperate leads for section A, B, and C. The color code and values are listed on the cap - sometimes hard to read, although easy enough to compare to the schematic for verification.

The highlighted areas show how each section is wired into the circuit. It is important to note that the actual wiring isn't as always straight forward as the neat schematic would suggest. In this case, wires from 14A and 14C both connect to the socket for the 6X5 tube - only 14A is actually part of that tube circuit 😄

It is common for tubes to have unused pins - so in this case, the wire for 14C goes to 6X5's unused pin 4, where the two resistors are tied - see the red circle above. This is a common trick to ease wiring and keep leads short - avoiding unwanted effects that may be caused by long leads.

The circled component is resistor R27 - with a value of 4700 Ω, 1Watt. Take a close look....

This is tied directly to capacitor 14C. Note the very dark color of the middle part - the body should be brown, like the top end. The value is indicated by the color bands - which should be, from the bottom, yellow, violet, and red. Without a schematic, you'd have to guess the value, as the red band is charred. The top silver band indicates a value tolerance of 10%. This resistor and cap are part of the rectifier tube circuit, which supplies the power to the whole mess - and over time, this part was getting baked - possibly due to the filter cap leaking and on the way to failure, or something 'downstream' has failed, and drawing more current than normal. To be determined 😁

And finally, something a bit silly to finish....

The resistor issue is easy to explain... the frog, not so much.

Now, off to creating the initial parts order - there is always some component that is overlooked 🙄

Next post, typical soldering procedure for C14 - A, B, and C 😄

Webcor Reel Table

Before digging into the electrical restoration, I'm going to work on the mechanics on the top.

This is due, in part, to a minor annoyance - the chassis is 'locked' inside of the case.

The prongs for the AC power cord protrude into an opening in the case. The entire unit drops into the case and is a tight fit, without wiggle room to tilt, tip, cajole, or otherwise position such that it will simply lift out. 🙄

There is a narrow access panel on the bottom, so that the tubes can be replaced.

To get the silly thing out, I bent the external tabs of a little protective box inside. Then, I drilled the rivets so that I could retract the silly thing.

To review, note the fit 😁

The dangerous electrical bits reside below 🔌

Get Bent

Zap!

Although that annoyance has been solved, I still want to work on the top, before extracting the silly thing.

That brings us to an amusing carnival of wheels, levers, springs, washers, and miscellaneous oddities. Refer to the first image of the top of the deck 😎. Sometimes, there will be service manuals with parts diagrams, etc. I haven't found one for this, although a more extensive search in the Tapeheads.net forums may help. I'll simply document part placement with photos.

There are two of these reel tables. Since they are relatively unencumbered with multiple springs and interlocking mechanisms, they are easy to disassemble.

Without a parts diagram, make sure you can reassemble things - take a photo, make a drawing....

Get Reel, so to speak....

Parts is Parts

There are varieties of bronze alloys used for bushings - some require lubrication, others are self-lubricating. If it is of the self-lubricating type, I'll simply clean all of the parts and reassemble. There is a simple friction clutch - the spring, felt pad, and washers - and a rubber tire that drives the reel table. Although not easy to see in the photo, parts of the clutch have little index tabs that require proper orientation. In this case it's easy to figure out if the whole mess ends up in a pile - in some cases, it's not so obvious, so take note 🤓

Next: Digging further into the reel table drive mechanics.

Webcor 2110 Reel to Reel Restoration

This Webcor 2110, ca. 1952, found its way into my collection of anachronistic, incredibly useful toys.

Oh Joy!

Moving parts are always more amusing for sound playback toys

This deck records and plays a monophonic signal in both directions - when the tape is near the end of the reel, you turn a knob to reverse the direction of the tape "...without bothersome reel turnover." 😃

There are two tape speeds - 3 1/4 and 7 1/2 inches per second. On a 7 inch reel, you can get a delightful 2 hour recording 😅 with an astonishing frequency response up to 10khz, with less than .5% wow and flutter.  Original price, in 1952, was $207.50.

Detail of the high-tech tape time counter

Beautiful mic - still works

These images are from an initial evaluation. It has all of the tubes, and is mechanically complete. Subsequent posts will go into more detail about the mechanical restoration for each section, followed by the electrical work.

First look under the cover...

Closeup, along the tape path by the heads. One head is in contact with the tape, and they alternate with tape direction. Eventually, I'll post little videos about the very unique mechanisms.

Head wear and oxide buildup. Always have dice on hand as little repair positioning aids 😄

Inside the head case (so to speak)

Missing some of the felt pressure pads. These gently press against the tape for good tape-to-head contact.

Schematic

The tubes are common if they are needed. The tricky part is whether the worn heads still work - aside from wear, sometimes a fine wire inside the head assembly will break. Heads are very rare. If they are shot, this still makes a great little guitar amp, for that sweet tube sound.

Next: Cleaning the topside mechanics.

Revox - Alive and Well

Until the Revox B77 MK1 found its way into my collection, I've had no experience with the brand.

I received the electrolytic capacitors, about 30 of them, from Mouser Electronics.  Posts about this machine, on the Tapeheads forums, recommended replacement of all the electrolytic, and motor drive capacitors. The motor drive capacitors were supplied by Erhard Audio.

The most annoying part of the project involved the parts on the tape drive, and power supply cards. These circuit cards are attached to the power transformer, and due to several soldered connections, required a little patience. The other circuit cards were easily removed.

The majority of parts replacement required extensive disassembly of the machine. The motor drive caps were much easier.

Step one - remove the case.

Next, remove the front panel.

Then, expose the motor caps, which hide behind the voltage selector.

Unsolder the leads to the old caps.

I was unfamiliar with this brand and type of capacitor. When I saw the black 'goo,' I wasn't sure if it was from internal pressure, or if this was the normal appearance for a sealant applied during manufacturing. Since the sealant looked different between the capacitors, I decided to replace them.

Responses from the Tapeheads forum indicated that these caps are filled with a clear oil. These did not have any drips or other signs of clear oil leakage; however, I replaced all three.

If these would have popped, perhaps some extensive damage could have occurred.

The caps are attached to the front panel, via a 1/4 20 threaded stub. Install the new ones, and resolder the connections. These motor drive caps are not polarized, as they are designed to work with AC voltages, so there is no need to worry about which terminals the wire pairs connect to.

After everything was reconnected, I gave it the smoke test - it powered up just fine. I then put it back in the case, reattached the front panel, and set it up for a test recording - for a full 10" reel - at 7.5 IPS - about 1 hour 8 minutes of audio.

Depending on one's taste in music, it might not sound right - this is some glorious, live, Sonic Youth from a show in Germany, 1996. It sounds exactly the way it should.

The right audio meter has a bad lamp. I tried to replace it some time ago. Due to the plastic in the meter housing, I gave up on it, as it was stuck so hard that I didn't want to break anything. There are certain parts that you really don't want to have to track down.

The machine is now to the point where it I think it should be reliable for a long time.

Revox B77

A Revox B77 MKI managed to find its way into my collection of audio toys.

From the Revox Classics page

Included in the trade...

The QC checklist - 1982.

The Specifications p33

Specifications p34

This machine was originally the Low Speed version, with 3¾ - 7½ IPS Record/Playback speeds, later converted to a High Speed, 7½ - 15 IPS. This modification required a high speed capstan motor, in addition to various other electronic modifications.

Before powering it up for the first time - it was in storage for a couple of decades - I removed it from the case to look for any signs of burnt, bulged, discolored, or missing parts. I was curious about user experiences with this machine - e.g. common failures, tape and maintenance recommendations, etc. A fantastic place for this is Tapeheads.net.

Tape! Not something that you can find at your local audio store... so I ordered a reel of ATR Master Tape. Another source is Full Compass.

Once I got the tape, I hooked the machine into a Gaines audio converter, to feed the Crown D45 amp, driving a pair of B&W DM602 S3 speakers.

D45

All is good - for awhile...

Electronic components age - just like anything else. One of the most common issues is the failure of electrolytic capacitors - as they age, they open, short, or turn into some resistive value between zero and the infinite.  This can cause any number of problems - anything from not passing audio, to flames jumping from the power supply! The other issue is the tantalum capacitors. Tantalums like to explode - that's another story...

I wanted to make a recording. The machine had been working perfectly - yet this time, the audio was extremely low in level. Often, reseating cards and various connectors, exercising switches, can solve the problem - as contacts oxidize and signals get messed up. Not this time!

The next step was locating a service manual. First, I checked the main power supply voltages - all were within specification. Then, I pulled out each circuit card to look for visible damage.

Well that was easy to spot...

Burnt resistor! Now, why did it burn...

R6 is the burnt resistor, upper right...

The underlined component, a 47Ω resistor, was toast. The circled component, C6, is (well, was...) a 220uf 25v electrolytic capacitor - that due to age, turned into a 20Ω resistor - causing excessive current to flow from the +21v rail to ground - and taking out the resistor.

At this point, I made made the decision to simply replace all of the electrolytics - so I made an inventory - comparing the actual circuit cards to the service manual, and ordered the parts.

Once I get the parts and get everything replaced, I'll post an update.

Wobbulator

An unusual piece of test equipment found its way into my collection of worn, forlorn anachronous  electronic items.

The Triumph Manufacturing Company of Chicago made this wonderful Model 830 Oscillograph Wobbulator.

An excellent description of this item can be found here... http://richardsears.wordpress.com/2011/09/08/triumph-830-wobbulator-oscillograph/

When I first started to examine it for possible restoration, it was clear that it would require more hacking than I'd hoped, some key parts have been removed. I will simply clean it up and use it as an unusual bookend.

The most beautiful thing I found inside is the CRT - I may display it in a little case. It is a beautiful example of early CRT technology.

Dumont 2501A3 CRT

This is a Dumont 2501A3 CRT, a 3" medium-persistance green fluorescent tube, using electrostatic focus. Inside the glass tube near the base, some hand-painted numbers suggest a manufacture date of January 1941, coinciding with the earliest appearance of data that I have found for this tube.

Decisions to make...

I was unable to find low voltage multi-section capacitors to replace C39 and C105 (dual section 1500uf@16 volts). This forces a restoration decision - gut the old cases and hide the new capacitors inside the can, or leave the new caps exposed.

These two multi-section capacitors have a cardboard shell, and I did not want to attempt gutting the shell, as it seemed much less sturdy than the typical metal cannister. Thus, I decided to abandon a strict cosmetic restoration. For my Atwater Kent and Crosley battery radios, I did take the time to hide new components inside old cans, or discretely underneath the chassis. For this project, I am more interested in function than museum display.

It isn't pretty. It just works. Purists will cringe.

New low voltage filter caps - nowhere to hide...

I was able to find new high-voltage multi-section electrolytics.

New multi-section 20uf@475v, next to the old.

C30 - initial solder removal.

I was able to avoid removing the originally connected components for the most part. This required careful desoldering to preserve the length of the original component lead, saving time in the long-run. The components were tested, and were within expected tolerances. Any component can pass simple tests and fail under power. I suspect that these will be fine.

I did remove two of the original resistors for C1, simplifying installation of the new one.

Original C1

New caps

Original input section paper caps...

New caps.

Chester remains unimpressed

I am waiting for a few more parts.