TheSamba.com :: View topic

Thu Nov 22, 2012 10:02 am

here’s my original radio knobs which are correct for an 8M radio.

i cleaned them up a little and mounted them onto the radio.

gary at brezelwerks offers repro knobs in the classifieds.

http://www.thesamba.com/vw/classifieds/detail.php?id=322749

i didn’t like the black knobs since they don’t match the ivory knobs on the rest of the dashboard. so i’ll keep the original knobs tucked away safe and sound.

i ordered ivory “bullet style” knobs which are actually correct for the earlier 5M radio. but they look so cool and so “50’s” i had to have them!

i also noticed gary offers a chrome insert for these knobs as well as a colored one, which can be any color you want. since i still have some coral red paint i mixed up a while ago, i decided my dashboard should be a “symphony in coordination.”

i used a small windsor and newton series 7 brush (really nice brushes!) to carefully paint a ring of coral red onto the knob. i also used a little rubbing compound to polish them up a bit more…after the paint dried, of course.

looking at the back of one of the knobs, the red arrow points to the center hole that the tuning shaft slides onto. the green arrow points to a larger bore.

it would be nice if this bore wasn’t there, especially since it isn’t necessary. the knob had a slight “wiggle” in it after installation on the tuning shaft.

i decided to make a shouldered bushing to replace the oillite bearing gary supplies in the dummy knob. this will tie the two pieces together.

i chucked up some brass rod into the lathe.

i also drilled a 3/16” hole through the center and reamed it .005” oversize (.1880” diameter) for a nice tight fit over my new titanium shaft (which slid into the hole perfectly).

i drew the part i wanted in solidworks and wrote the g-code in gibbscam as usual.

here’s the part still attached to the stock.

i slid the dummy knob onto the bushing.

then i slid the tuning knob onto the bushing.

the brass bushing after cutting it off of the stock…

right then, here’s the knobs laid out in front of the radio.

the treble/bass knob has a “bosch symbol” cutout in it as seen below.

then i installed the rest of the knobs.

Thu Nov 22, 2012 10:03 am

okay…most of you will think i have fallen off the deep end with this next phase of the project. if you can’t stand how anal i am, please stop reading right now.

if we look at the right side of the radio before restoration, there’s a “25” stamped on the chassis (red arrow). could it be an inspector’s stamp? maybe the factory assembly worker? regardless, just for shits and giggles, i thought i’d see if i could reproduce it.

i drew a stamp in solidworks…trying to match the font the best i could.

i have some machinable wax left over from a previous project, which is a synthetic wax used for rapid prototyping…also, it’s easy to machine. i wondered if i could use it to make the stamp.

i squared up a block that’s ½” x ½” x 1” long as seen below.

then i used gibbscam to write a surface milling operation using a miniature .025” diameter ball end mill.

you can see the tiny end mill in the photo below. it’s just going back and forth… real slow so as not to break the end mill. this took almost two hours.

here’s the finished stamp.

next i sprayed gloss black paint onto a scrap of steel and made a few test stamps.

after i started to get the feel of it, i stamped the chassis. the clear paint on the chassis was well cured…so, if i didn’t like the stamping, i could just wipe it off and try again. after a few tries i got one that looked pretty good. i tried to keep it random-looking and uneven.

Thu Nov 22, 2012 10:04 am

i had so much fun making the “25” stamp…

did you notice the original vibrator had “852 40” stamped on it?

here’s the original vibrator (placed above the radio for reference) and the stamp i made to the right.

the vibrator after stamping.

finally, here’s a couple pictures of the completed radio.

Thu Nov 22, 2012 10:04 am

there more parts that need to be restored in my hi-fi stereo!

if you remember, there’s a screw and star washer on the back of the radio (green arrow).

the support bracket bolts to this. in the photo below, you can see the bracket still attached on the other end to the wiper motor (red arrow).

here’s the bracket ready for restoration.

after bead-blasting, i painted it with a zinc-colored silver, then clear-coated it.

Thu Nov 22, 2012 10:04 am

next we have the screen that sits behind the chrome speaker grill on the dashboard.

i’ve read some threads on the samba that mentioned this part was painted black…maybe with some flocking? but i found no evidence of this on my screen. it looked like it was zinc-plated.

here’s a close-up…there’s a little dirt on it. otherwise it looked silver to me.

so, i bead-blasted it, painted it with the same zinc-colored paint as mentioned previously and clear-coated it.

Thu Nov 22, 2012 10:05 am

this photo was taken by the chrome shop. my “big M” trimplate and screws can be seen before chroming…above them is the speaker grill.

the speaker grill was able to be saved. it chromed up real nice! i also installed the screen in this picture.

Thu Nov 22, 2012 10:05 am

here’s my original speaker mounting plate. this plate has four studs on it which is used for mounting a 6”x9” speaker.

after sandblasting…

my car came with a 5”x7” speaker. to mount this speaker, a second mounting plate is required. the 5”x7” speaker mounts to this plate…then the assembly mounts onto the studs of the 6”x9” plate.

after sandblasting…

both plates were treated with ospho, then zinc-chromated after they were dry.

i hung the plates from a fixture i have here at the shop.

for the past few years, i have been borrowing a friend’s iwata paint gun. i finally decided to get my own.

the photo below shows my new iwata supernova LS400 spray gun. you can tell it’s a base coat gun because of the gold cap.

after this first use, i have to say i love this gun!

while i waited for the paint to dry, i used the outdoor grill as an oven and made some bavarian pretzels from scratch…dipping them in a lye bath, of course.

here’s the finished 6”x9” mounting plate…

…and the 5”x7” mounting plate.

Thu Nov 22, 2012 10:06 am

i was missing the original 5”x7” speaker. however, i found one in the classifieds.

turning the speaker around, the red arrow points to (i believe) the magnet.

i took it to a speaker shop to see if it could be reconed and he said because of the magnet touching the side, it’s junk…can’t be fixed.

i mentioned in a previous post that i found an antique radio guy locally. he gave me the speaker wire i soldered to the radio in an earlier post.

he had a 5”x7” speaker which he sold to me for $4.

here it is below the original motorola speaker.

Thu Nov 22, 2012 10:06 am

there’s a few differences in the speakers, but i decided to use it unless i can find another one.

if you look again at the previous photograph, you’ll notice the original speaker has “motorola” and “golden voice” written on it.

since i made stamps for the radio…let’s take care of the speaker!

i drew a couple of stamps in solidworks as before.

here’s the “motorola” one being made on the mill with the .025 diameter ball end mill as before.

here’s the finished stamping of the speaker. The stamps are at the bottom of the photograph.

Thu Nov 22, 2012 10:06 am

turning our attention to the front of the speaker, there’s a few tears in the paper cone (red arrows).

i also took this speaker to the speaker shop. the guy made several calls and told me he could not get this speaker reconed.

it’s a 5”x7” speaker…but, because of the ears sticking out of the frame, which is where the mounting screws go, it’s actually a smaller size. he couldn’t find a new cone that would fit.

he told me i could fix it myself with white glue and tissue paper. so, i went to the dollar store to get some kleenex. i looked for the cheapest stuff i could find…without perfumes, lotions or whatever.

i tore off a few pieces and carefully glued sections over the tears in the speaker.

here’s the speaker after the glue dried. i also diluted some white glue 50% with water and brushed it over the entire cone. it looks like i had a few dry spots. but, it seems to have done a good job. it feels pretty strong.

here’s the speaker, the mounting plate (without the studs) and four new #10 x 5/16” tapping screws.

the completed assembly…

Thu Nov 22, 2012 10:07 am

i purchased a new dual mount antenna from wolfsburg west.

here it is mounted to the car using the original mounting holes in the driver’s side fender.

Thu Nov 22, 2012 10:07 am

here’s all the finished parts thrown together.

wanna see it run?

now i’m officially done with the restoration of my motorola 8M radio.

cheers!

Thu Nov 22, 2012 10:08 am

Motorola Sales Brochure from 1958

I found a Motorola sales brochure from 1958 on evilbay. I won the auction, scanned it, and sent it to Everett so it’s available on TheSamba’s archives:

http://www.thesamba.com/vw/archives/lit/58motorola.php

It’s nice to have a contemporary source of information. Also, the illustrations are awesome!

Let’s take a look.

While reading the brochure, I learned that the “M” in the model number designates the radio as a manual tuning radio. The push-button radios in later years have an “A” in the model number. For example, the VWA8 (which was “new” for 1958, and can be seen on page 19 shown below):

By the way, look at the radio advertised under the VWA8. It’s a VWA7 radio. It’s a new “retrofit” radio for the earlier dash of our oval beetles.

The 8M radio is shown on page 11…

Page 12 highlights the features of the 8M…

It’s interesting to see a different faceplate mounted on the radio in the illustration at the bottom.

Page 4 shows “Deluxe” trim plates available. AK159 is an option for the 8M radio:

Thu Nov 22, 2012 10:10 am

Glass Dial Scale

Let’s talk a little bit about the glass dial scale. Don’t forget, the lettering on the 5M is different from the 6M, the 7M and the 8M as mentioned earlier.

Here’s a photograph of the dial scale that came on my 8M radio.

After the word Motorola, “Volumatic” is written across the top. Have you ever wondered what it meant?

if we look on page 3 of the 1958 sales brochure…

…the definition of Motorola’s Volumatic is given:

First—There’s never any need to reset the volume level when you change stations! The volume stays constant up and down the dial, weak signal or strong.

Second—No matter where you are—on bridges, among tall buildings or under viaducts— just as long as there is a signal present, Volumatic minimizes “signal drop”. You get the signal loud and clear at the pre-set volume level.

So, it seems there used to be a problem with the volume getting louder or softer depending on how well the radio was receiving the signal. It’s something we take for granted nowadays!

Take another look at the dial scale. Have you noticed these two symbols in the middle (the red arrows in the photo below)?

They are symbols for civil defense. If we look once again at the sales brochure, under the description of the 8M radio on page 12…

…it states “Civil Defense Frequencies clearly indicated.”

I looked up “United States civil defense” on Wikipedia. The article mentions in the event of an emergency:

A few primary stations would be alerted of an emergency and would broadcast an alert.
After broadcasting the message, all radio communications would cease except for two designated lower power AM frequencies (640 and 1240 kHz). This was designed to prevent enemy planes from using transmitters as navigation aids for direction finding.

This would have been an extremely important feature for a radio back in 1957! We all know an atomic attack by the Russians was imminent back then. So, racing back home to get into the concrete bunker buried in your back yard would have been vital for survival of you, your family and the human race! (Think Christopher Walken in “Blast from the Past”).

Works Cited

“United States Civil Defense” Wikipedia. The Free Encyclopedia. Wikimedia Foundation, Inc. 27 April 2012. Web. 30 April 2012.
<http://en.wikipedia.org/wiki/United_States_civil_defense>

Thu Nov 22, 2012 10:10 am

SAM’S illustrations:

If you’re not familiar with SAMS photofact manuals, look here:

www.samswebsite.com/

They offer service manuals for consumer electronics. The company was founded in 1946 by Howard Sams. They would buy a radio to reverse engineer the schematics, parts numbers, etc.

Here’s the photofact numbers for the “Big M” radios:

5M radio = 295-7 (also available in 12-volt = 5M-12)
6M radio = 331-9 (also available in 12 volt = 6M-12)
7M radio = 331-9
8M radio = 411-12

I purchased the schematic for my 8M radio. It’s available in the technical archives on the samba.

http://www.thesamba.com/vw/archives/manuals/big_m.php

Thu Nov 22, 2012 10:12 am

Assembly into the Car

Since I’m far from installing the 8M radio into my ’57 beetle, I drew all the parts in Solidworks to provide clear illustrations for installation.

I used the installation guide (available in the archives) for guidance.

http://www.thesamba.com/vw/archives/manuals/53_56_motorola_big_m.php

Here’s a rendering of the oval beetle dashboard…painted coral red, of course!

By the way, the keychain I rendered exists…it’s made from felt. I bought it from the official Oktoberfest website. The edelweiss reminds me of my Bavarian roots and the felt is soft enough not to scratch my dashboard while driving!

And here’s the back of the dashboard:

Thu Nov 22, 2012 10:12 am

Let’s start with the blank dashboard:

There are 3 strips of rubber glued to the dash. All 3 are 2mm thick. The center strip is 10mm x 75mm. The outer strips are 10mm x 35mm and are located 125mm from the center (center-to-center distance).

Next, the screen is installed into the chrome grill. Then the assembly is inserted through the six slits cut into the dash.

i noticed the tabs are not bent at a 90º angle at the back…

They are “twisted” with a pair of pliers instead!

After the grill is secure, 6 rubber seals are glued onto the back of the dashboard, covering the twisted tabs. This probably helps prevent fumes from the fuel tank reaching the cabin.

The seals are available from Wolfsburg West.

http://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=111857241

Thu Nov 22, 2012 10:13 am

Next, we need to install the speaker.

The speaker mounts to a metal plate provided in the kit with the motorola radio.

Study the rendering below carefully. There is a top and a bottom.

There is a bigger gap between the top edge of the plate and the first set of holes.

I highlighted two of the holes with red dots. This is where the #6 x 7/16” self-tapping screws mount the plate to the dashboard.

Here’s an exploded diagram for you. Notice I drew a gasket between the speaker plate and the dashboard. There were remnants of a gasket on my beetle. However, it was several years ago when I removed it. So, I don’t have any measurements.

Here’s a picture of the back of my dashboard. You can see the ghost image of the gasket. I remember it looked like foam weatherstrip.

i measured the image of the gasket. It’s about 10mm wide weatherstrip. The oval is 145mm high x 225mm wide (center-to-center).

Here’s a picture with the gasket peeking out behind the speaker mounting plates.

Thu Nov 22, 2012 10:14 am

6”x9” speaker installation

The exploded diagram below shows the hardware required to mount a 6”x9” speaker.

It mounts onto the studs of the speaker plate. Notice there’s a wingnut on the top right stud. I haven’t found an explanation for this. I noticed the stud is behind the windshield wiper motor assembly. Perhaps a wrench is difficult to get back in there. So, a wingnut is recommended.

Thu Nov 22, 2012 10:14 am

5”x7” speaker installation

If you are mounting a 5”x7” speaker, you will need another speaker mount as mentioned above when i restored my 8M radio.

Let’s have another look at page 12 of the motorola brochure mentioned earlier…

In the description for the 8M radio, a 5”x7” speaker is included with the kit for the 8M radio.

If you review my 8M radio restoration, I mentioned that I bought a 5”x7” speaker in the classifieds, which turned out to be junk. The speaker included one of these secondary mounting plates and it came out of a ’56 beetle.

So, perhaps the 6”x9” speaker came in ’55 and earlier cars, and the 5”x7” speaker came in ’56 and ’57 beetles.

Pressing on…the 5”x7” speaker mounts to the plate with (4) #8 x 3/8” self-tapping screws as seen below.

Then, this assembly mounts to the other speaker plate (with the studs) just like the 6”x9” speaker as seen below.