Some of my friends and customers used to joke around about my magic screw driver as problems seem to disappear when I show up. (Did you bring your magic screw driver?!) My cousin Mike Spikes of American Toy, llc was inspired to draw this sketch.

I became a professional electronic technician when micro processors had 8 bits and ran on a 3.14 mhz clock - 1973. I excelled at component level trouble shooting working on early graphic workstation terminals for Tektronix. In 1977 I quit Tek and started Musician's Bench in Portland, OR. Portland needed someone to provide this service at the time so it was easy to sign up for accounts with Arp, Moog, Oberheim, SCI, Roland, Yamaha, Fender Rhodes, Wurlitzer etc. I attended factory training at most of these companies and provided service in and out of warranty during the "glory years" of American designed and manufactured electronic music gear.

Disgusted by dealings with the public at large and other non technical aspects of running the business, I was inspired to get away from the store front repair operation. A following of loyal customers from the past still keeps me in the business at a hobby level and I've kept all the documentation, parts and other resources required to work on a lot of vintage gear - mostly keyboards.

My favorite customer is the owner who wants to learn what they can about working on their own gear. My passion for sharing knowledge and the willingness to do so keeps me connected to the repair business.

Read and learn from these music tek bench stories!

Music electronic technician Larry Church discusses various bench projects with relevance to teaching basic skills valuable in working on vintage music equipment. Larry attended factory training at companies such as Arp, Moog, Yamaha and Sequential Circuits, and provided warranty service for these companies and others such as Rhodes, Gibson, Wurlitzer, Marshall, etc.. Basic skills, common sense, general knowledge and trouble shooting mentality are discussed here.

Sunday, December 20, 2009

Moog MG-1 cabinet restoration

My customer, Dave, located me in an internet search for synthesizer repair.  Dave is a component level trouble shooting technician himself having worked primarily on computers and entertainment electronics for 30 years or so.  He was not seeking my technical expertise but rather my woodworking skills, so this project merges two of my strongest subjects: vintage synthesizers and woodworking.

Dave is the proud owner of a Radio Shack MG-1 that he is restoring and customizing. The MG-1 was made for Radio Shack by Moog Music back in the 80's.  The case for the MG-1 (Moog Rogue also used the same case design) is a little different than most instrument cases in that the front panel and bottom plate are held together structurally by the molded plastic end panels.  These panels have slots in which the edges of the metal panels are inserted and attached with a bead of hot melt glue.  The unit Dave is restoring has the left end panel missing and he requested wooden end panels be fabricated to create a custom look for his Radio Shack synthesizer.

There is at least one company already specializing in making wooden synthesizer cabinet parts.  Synthwood has an extensive offering of custom parts and services but they do not list end panels for the MG-1 as an available product.  These Moog panels differ primarily from others in that they have a structural function and they are not simply cosmetic. The sheet metal parts connect directly to, and are supported by, the end panels.  Additionally, the panel includes a filler block which encloses a space between the ends of the keyboard assembly and the end panels.  This makes these parts significantly more complex to fabricate than a cosmetic panel that attaches to an existing chassis with a couple of screws.

Router jigs to accomplish the precise machining required were designed and constructed (see article on "Jigs").  Routing for each end panel is done in two operations - one operation for the front of the panel to receive the bottom plate, and another operation for the back and top to receive the front panel assembly.  The left and right panels are a mirror image requiring separate jigs, so: four steps requires four jig designs.  Then the filler blocks are fabricated and attached to the panel with glue and screws. Finally the bottom edge of the panel is scored 1/16" deep and half way across the thickness of the board to allow the bottom plate to recess flush with the outside bottom edge of the panel.

I've been looking for a reason to design and construct a router jig of some sort.  That skill set will be handy for upcoming plans I have for myself, so I agreed to give it a shot.  Building and fine tuning the jigs was certainly a learning experience.  The experience was enhanced by the fact that the sheet metal parts I had to work with appeared to be bent and torqued from original specs. 

Now that I have the jigs I can make these parts fairly efficiently, though it is a time consuming process.  When someone asks I think I'm going to say "$70 and I'll make a pair for you out of wood on hand (see Cherish Earth Project) or send the wood of your choice and the price is the same.  The Dimensions should be at least 5 1/2" X 28" (or 2 ea. X 14") and 3/4" thick finished or 4/4 rough.

Pictured here is a piece of black walnut salvaged from a dunnage pile somewhere In Tualatin, OR, that I selected to make the first finished prototypes from.  I wanted to see the sapwood edge left parallel to the sloped front leaving the bottom to be cut across the grain.  Another approach is to have the grain parallel to the bottom edge so the cross grain cut edge is visible from the top.  This cross grain cut produces some fascinating grain patterns and is a common technique sometimes used in making gun stocks. 

The hot melt glue connection used by Moog in this cabinet design has some significant characteristics.  It does an excellent job filling voids and is easy to apply contributing to an inexpensive manufacturing process.  On the down side, hot melt glue does not have particularly great adhesion to the plastic and metal surfaces being connected in this application. It remains somewhat pliable, especially in warmer temperatures.  I suspect that, if left in the direct sunlight for any length of time (never a good idea for any electronic device) the case warms enough to contribute significantly to the pliability of the glue connection.  Eventually these connections tend to come apart.  In the case of Dave's MG-1 the condition resulted in a lost end panel  Not a good design for an instrument destined to become a collection piece!

My suggestion to Dave is that he assemble his MG-1 using epoxy instead of hot melt glue.  Loctite makes a 5 minute epoxy kit that comes with a small scale auto mix nozzle that looks to be about the right size for flowing a bead into the routed out slot.  I bought some of this for about $5 at Home Depot, but I see that Amazon has it on line for $1.99!

Maybe we can get Dave to comment after the restoration is complete.  He is replacing pots, sliders, caps, etc. and I'm expecting a call when he is ready to calibrate the VCO and VCF.


  1. Hey Larry. This is nice looking work! I have an MG-1 that has served me for many years. Perhaps I should give it some comfortable end cheeks as well... Should you or your customer be considering adding MIDI I warn you and your friend against the Synhouse MIDI retrofit--it is of questionable quality. greetings, a

  2. Hi Larry. You fixed a Moog Sonic Six for me about 14 years ago. It really needs servicing again. Do you still do that kind of work? If not, can you recommend someone? You can reach me at jason at jekphoto.com. Please let me know if you can help. I appreciate your time.


  3. Hi Larry,

    I'm interested in getting a pair of wooden end panels for my MG1. If you still have the jigs and time, please contact me: dan at dextersinister.com


  4. Hey Larry,

    I would also like to get a pair of those spiffy end panels for my rogue. I can be reached at frozensound at hotmail if you have the time.

  5. Thanks for
    Nice information.

    1. So sorry for those of you that posted here and never heard back from me. My Google account was pirated by some unknown bug on my old computer that nobody could correct. I now have a new computer and am cleaning up old issues, so, try posting here again, or contact me directly 503-632-1234, mintlake at bctonline dot com or on Facebook pages (personal) Larry Dee Church (electronics) Technician Larry (woodworking / materials) Oregon Territory Tree Parts).

  6. So sorry for those of you that posted here and never heard back from me. My Google account was pirated by some unknown bug on my old computer that nobody could correct. I now have a new computer and am cleaning up old issues, so, try posting here again, or contact me directly 503-632-1234, mintlake at bctonline dot com or on Facebook pages (personal) Larry Dee Church (electronics) Technician Larry (woodworking / materials) Oregon Territory Tree Parts).


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