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Consoles => Magnificent Magnavox => Topic started by: electra225 on April 11, 2017, 07:30:28 PM

Title: New, improved cabinet back
Post by: electra225 on April 11, 2017, 07:30:28 PM
My project for the summer is to design and build a new cabinet back for my Concert Grand.  It has long been my contention that Magnavox instrument cabinets, with the possible exception of the Symphony series, are poorly ventilated.  I am therefore going make an "improved" version for my instrument and see if I like that better.  A side benefit to my new back will be to make the tubes easier to see.  The CG, the Imperial and my "maybe" Stereo Theater will all benefit from my new back if I get the job done properly.  If there is any interest in this project, I will be happy to document with pictures and share as I go along.  If not, then I will enjoy the project on the sly.

Simply, I plan on using lauan and some wire mesh I have to make the back.  The original back is photofinished Masonite, so the lauan will be wood-grained like the original.  I will integrate the FM antenna like original and even reproduce the model number sticker, if I can do it or have it done.  Mine is quite yellowed, so it will take some work to make an acceptable replacement.  The rest should be a matter of measuring and a little ingenuity.  I will finish both sides, but the side that shows will be smoother finished than the side that goes toward the cabinet.

Title: Re: New, improved cabinet back
Post by: Bill on April 11, 2017, 07:42:50 PM
Hi Greg, and welcome home!

Sounds like you are already busy with yard work and stuff.  And the MAYBE on the Home Theater....does that mean you are close to getting one? 

I saw the Imperial yesterday but have not brought it home yet.  Cabinet is very nice, but not sure if it works yet.  I just need the weather to cooperate so I can get it home. It's Michigan!!!!

Bill
Title: Re: New, improved cabinet back
Post by: electra225 on April 11, 2017, 07:50:30 PM
No closer to a Home Theater.   :(  I'll find one.  Half the world is looking for one for me.

Just put the old "mud and snows" on the Imperial, put it in four-wheel drive and get 'er done.   ;D

I shall wait with baited breath for the arrival of your Imperial.  If it does not work, I'd bet there is not much wrong with it.   ;)
Title: Re: New, improved cabinet back
Post by: Bill on April 11, 2017, 08:02:29 PM
Never thought of putting mud and snows on the Imperial.  If the weather does not straighten out I might just have too.  When you have time we should but our heads together, yousr more than mine, and figure out the mystery machine.

Have fun,
Bill
Title: Re: New, improved cabinet back
Post by: electra225 on April 11, 2017, 08:31:19 PM
I look forward to helping any way I can. 
Title: Re: New, improved cabinet back
Post by: Harbourmaster on April 11, 2017, 09:43:32 PM
Just like they made em back in the 30's.  Should work just fine.
Title: Re: New, improved cabinet back
Post by: Billsmith60 on April 11, 2017, 10:01:30 PM
Yes I would like to follow your back panel mod, with lots of pics, thanks
Title: Re: New, improved cabinet back
Post by: racfan9 on April 11, 2017, 10:11:00 PM
Hey Electra225, I definitely would be interested since mine is missing the back. But I have a lot to do to mine,"(electrical and woodwork)" before the back panel becomes an issue. Good luck with yours.
Title: Re: New, improved cabinet back
Post by: electra225 on April 12, 2017, 04:38:26 PM
The good news is I will have a cardboard pattern and the original if you need a pattern or measurement.  And, of course, my replacement.  We should be able to come up with something that will work for you. 

You can call me Greg.  Electra 225 is the model of my Buick and my username on here.  Nice to meet you!   :D
Title: Re: New, improved cabinet back
Post by: TC Chris on April 12, 2017, 06:24:49 PM
The good news is I will have a cardboard pattern and the original if you need a pattern or measurement.  And, of course, my replacement.  We should be able to come up with something that will work for you. 

You can call me Greg.  Electra 225 is the model of my Buick and my username on here.  Nice to meet you!   :D

I recall a local newspaper article about name changes.  The reporter interviewed the local probate judge, who handles name changes in Michigan.  The judge was amused by various choices.  He said that there was one guy who liked his car, so he changed his name to "G.T. Mustang."  I understood completely.  I had just bought my sturdy red '86 Mustang GT.  But unfortunately, the name was already taken.

Chris Campbell
Title: Re: New, improved cabinet back
Post by: electra225 on April 12, 2017, 07:06:18 PM
I like Electra just fine.  It is nice if we know each other's names.  I don't get touchy either way.  You can call me whatever you'd like.   As long as you don't call me late for supper....... ;)
Title: Re: New, improved cabinet back
Post by: TC Chris on April 12, 2017, 07:53:53 PM
I like Electra just fine.  It is nice if we know each other's names.  I don't get touchy either way.  You can call me whatever you'd like.   As long as you don't call me late for supper....... ;)

That's why I always "sign"  mine with the full name.  It makes me responsible for what I'm saying.  The anonymous comments on the internet are usually the ones that are vicious or cruel or nasty.  I'm on  statewide listserv at work and we're required by the list rules to post name AND address. 

This old-hifi group is polite and considerate.  I'll bet we've got political and religious opinions that run a wide range from left to right and maybe up and down too, but we manage to control ourselves so we can talk about cool consoles, making them work, and a few ancillary things like records and cars.  It's a good model.  If I only had friends who agreed with me politically, I'd be a pretty lonely guy.

Besides, I bet everybody thinks I'm the bass player from the Silver Bullet Band.

Chris Campbell
Title: Re: New, improved cabinet back
Post by: Bill on April 12, 2017, 08:12:09 PM
I like knowing names as well, it just makes everything more friendly.  I also like knowing where everyone is from, at least the state they live in.

Bill
Title: Re: New, improved cabinet back
Post by: electra225 on April 12, 2017, 08:39:18 PM
For the last two or three days, Bill, I have been living in a state of disarray!   ;)
Title: Re: New, improved cabinet back
Post by: Bill on April 13, 2017, 09:17:32 PM
I think I know that disarray person!

Bill
Title: Re: New, improved cabinet back
Post by: Deutschgerg on April 17, 2017, 01:17:33 PM
I agree with y'all about knowing each other's names and what area we are from. I chose my moniker several years ago when I was leery of disclosing anything personal on the first forum I ever joined. I realized on this forum there are some really decent folks who are always willing to provide assistance and share good information so I started signing off with my real name. BTW, my moniker, "Deutschgerg" is from my German heritage (Deutsch means German) and "gerg" my name spelled backwards.

Regards,

Greg
Title: Re: New, improved cabinet back
Post by: electra225 on May 23, 2017, 11:08:24 AM
The cabinet back project is progressing.  Slowly.  The golf cart died and that project got blown all out of proportion.  That is a story for another thread.

I have the pattern made and have that drawn out on the lauan.  That's as far as I have gotten.
Title: Re: New, improved cabinet back
Post by: electra225 on August 20, 2017, 07:03:05 PM
Today I had to start this project all over again, from scratch.  Long story why.  I'm actually happier with the result this time and it was tons easier to do, it seemed like.  I made some changes than I believed would enhance the "optics" of the project.  I am done with the pattern and have taken pictures.  When I transfer the pattern to wood, I'll document that and share those pictures if there is interest. 

Let me assure you all that there were no factory Concert Grand parts, great or small, harmed or changed in any way for this project.  I am going to retain the original back in case I want to sell the instrument.  I have a dry storage closet in the garage I can keep it in without fear of damage.

The first picture is the original back panel laying on a chunk of cardboard.  Poster board would actually be better, but an old screen door container was free.  It worked okay.  I am not going to use the pattern as a pattern that I draw around, but as a template.  I will actually measure and mark the lauan, then compare to the pattern before I cut.  Probably a weird way to do it (make a pattern and not use it, per se) but that is the way I was taught.

The second picture shows how I marked the outline of the holes in the original back.  Subsequent pictures show the process of "squaring up" the holes so I can cut the panel out, preliminarily. to see how it fit and what I wanted to modify.
Title: Re: New, improved cabinet back
Post by: electra225 on August 20, 2017, 07:13:17 PM
A couple tidbits.  You may notice in one of the pictures, I cut the pattern extra large.  I cut around my pattern with tin snips.  Then I cut the actual pattern to size with a single-edge razor blade.  The wife obsconded with my Exacto knife.   ;)

The following pictures show the first cut of the pattern actually fitted to the cabinet.  I have the opening cut out in the exact location of the original "holes."  You can see how restricted air flow would be when you see the output tubes nearly covered.  The later pictures show how that will change. 
Title: Re: New, improved cabinet back
Post by: electra225 on August 20, 2017, 07:30:30 PM
In the top picture of the ones I just posted, there is an irregular cutout around the Multiplex adapter.  This is a change I made from my first pattern.  The third picture shows how I used the piece I cut out of that hole to make my patch.  I cut the patch and stuck it to the pattern with clear shipping tape.  This change will make that area look neater and makes the MPX adapter look better.  I had not had the back off my CG for two years.  It is still in pretty good shape.  I am going to have to polish the bottom for the Multiplex adapter and clear coat it this time.  It turned dingy.  There is a cover on the Phantom Control chassis that is in the bottom of one of the pictures.  It will require polishing and clear coating as well for the same reasons.  The rest looks pretty good still.  Light dusting and detailing should suffice.  I am not going to make any effort to make the Magnavox wiring mess look neat.  They did not want it neat from the factory, or they would have made it that way.  I have a dirty control, AGAIN, so this would be a good time to pull the tuner and give it a good cleaning.  I have a set of "close" wires for the Multiplex adapter which will eliminate part of the rat's nest in that area.

Notice as the project progressed, how I canned the idea of rounded/beveled/some kind of fancy corners.  Square corners proved to be the neatest in appearance and will be easier to get straight and even.  I was trying to get too fancy, perhaps a mistake I made on the first go-round.  This will be a cabinet BACK.  It won't be seen that much, and when it is, people will be looking at all those sparkly tubes!   ;)
Title: Re: New, improved cabinet back
Post by: Motorola Minion on August 21, 2017, 08:55:54 PM
Looks great and gives me some ideas. My Motorolas have bigger round holes but that is not much better, but way bigger than my 1960 Symphony, which has openings in the bottom to compensate for those tiny holes.

Will you be putting window screen over the openings, attempting to keep the dust out? I have seen that done on organs, with the dozens of tubes showing quite well through it.
Title: Re: New, improved cabinet back
Post by: electra225 on August 22, 2017, 08:05:05 AM
I will use wire mesh over the holes.  That will be in Part Three of this little project.  Next step is to transfer to wood.
Title: Re: New, improved cabinet back
Post by: TC Chris on August 22, 2017, 07:05:25 PM
I like your project.  Heat is the great enemy of our old electronics devices.  The manufacturers had to make compromises for safety, aesthetics, and design.  We can give more weight to durability.

Chris Campbell
Title: Re: New, improved cabinet back
Post by: electra225 on August 22, 2017, 10:15:55 PM
My main objective is to improve ventilation.  My second objective is to make the improved back look as good as the original, which is photo-finish wood-grained tempered 1/4" Masonite.
Title: Re: New, improved cabinet back
Post by: Harbourmaster on August 23, 2017, 06:03:41 PM
Looking good Gregg. 


Might I suggest that building the final product out of Masonite will be more durable than a Luan door skin. Of course you can't do photo finish like the original but you could do a Faux painted finish that would work just as well. My S-31 extension speaker has just such a finish on the back.
Title: Re: New, improved cabinet back
Post by: electra225 on August 23, 2017, 08:43:11 PM
I thought about using tempered Masonite, but decided on lauan.  I made a couple smaller backs for table radios with scrap lauan and liked how they turned out.  Lauan is easier to work with, to machine, than Masonite with the tools I have available to me.  Plus, there is no place close to me here in Bugtussle that has nice tempered Masonite.  Additionally, on the bottom of my new back, it will only be about an inch and a half wide.  Tempered Masonite will be pretty flimsy cut that far out.  Lauan will be stronger, coupled with the mesh I am planning to use.  I am not 100% certain that the mesh I'm using is the best I can get, just the best I've found.  I reserve the right to change it later if I find some I like better.
Title: Re: New, improved cabinet back
Post by: Bill on August 24, 2017, 06:53:15 AM
Great job Greg! 

Bill
Title: Re: New, improved cabinet back
Post by: 19and41 on August 24, 2017, 07:10:55 AM
Looking good!
Title: Re: New, improved cabinet back
Post by: electra225 on September 03, 2017, 01:24:59 PM
First, allow me to pat myself on the back.  The pattern I made for this project proved to be spot-on.  Dead perfect.  I never have drawn a perfect pattern in my life, didn't really think it was possible.  As I said before, I did not use this pattern to draw around, but to refer to by measuring it and transferring those measurements to the lauan.  There was a member who said he did not have a back at all for his Concert Grand.  If I could get my pattern to him, he would be in business.

I did another thing when I transferred to lauan.  Initially questioning the accuracy of my pattern, (and typically getting the holes in the wrong spot) I laid the original back on the sheet of lauan, lined up a corner and a side and drew around the back.  I bored the holes using the original back as a pattern.  After I cut the back out of the lauan, I trial fit the new back to the cabinet.  It fit like a glove, every hole.  That has NEVER happened before for me. 

I own a cheap little Black and Decker jig saw.  My friend has high-end woodworking tools.  He loaned me a Freud jug saw.  My goodness, what a difference.  Although I did not (did not expect to) get a perfect cut on my holes, I got a good enough cut that I could simply "sand 'er straight" like my Uncle Fort taught me years ago.  I sanded the edges and filed the corners to get everything finally square.  I allowed a eighth of an inch or so for sanding so as to not mess up my measurements. 

I sanded both sides of the back with 320 grit.  Then I stained the back without sealer.  I decided sealer would be best, so I sealed the front with a wash coat of unwaxed shellac.  Then stain.  After this dries well, I will put on at least three coats of shellac on both sides.  The back side will stay like this.  The front side will get sanded and perhaps more shellac.  I want to use black grain filler, but sparingly.  I used American Walnut stain, which is pretty close to what I wanted. After I get the shellac on, I will use grain filler on the edges, then darker Walnut stain to hide the end grain.  If this is not what I want, I can always paint the edges with black paint.
Title: Re: New, improved cabinet back
Post by: 19and41 on September 03, 2017, 04:59:36 PM
Sounds like your extra care has paid off!
Title: Re: New, improved cabinet back
Post by: electra225 on September 03, 2017, 07:22:09 PM
I have also learned that there is a difference between "contractor grade" lauan and "trim grade" lauan.  The last I got, apparently, was trim grade as there sure is a difference.  Contractor grade is all Menard's stocks.  Contractor grade is harder to refinish and work with.   
Title: Re: New, improved cabinet back
Post by: electra225 on September 09, 2017, 12:16:38 PM
I have the new back done and on the cabinet.  I made a couple mistakes that I had to correct.  First, I used staples marked "1/4 inch", but turned out to be 5/16".  They poked thru.  I had to take a day and fix that.  Then I noticed that I did not stain an edge of the back, so that had to be fixed.  Otherwise, I'm happy with it.  If I make another one, I'll make the cutouts around the amps about an inch narrower, so the mesh does not touch the cabinet.  I'm not sure what that would hurt, if anything, but I would feel better.  The mesh I used was unpainted, so I used a can of barbecue grill paint I had on hand.  That actually looks pretty good.  I used a shellac finish, since I could not find any lacquer and I really did not want to have to rub poly out to kill the shine.  I used clear coat on the cover for the MPX and the cover on the Phantom Control chassis.  I still have a wonky MPX adapter for some reason.  It works okay for about 15 minutes, then loses volume.  I tested the tubes and all the connections.  My next step will be to substitute the tubes and leave the back off until I'm sure everything is okay.  There is not much to one, so the problem should be a simple one.  Probably something I'm overlooking.  I was anxious to get the back on.  I hope to make another back for my Imperial this winter. 

I have pictures if anybody is interested.  I need to download them from my camera to the computer.

My wife has informed me of her fear that the new back may cause heat to burn the paint off the wall now.   ;)
Title: Re: New, improved cabinet back
Post by: 19and41 on September 09, 2017, 03:50:09 PM
Post the pictures,  I'd like to see them.  Glad you got it finished.
Title: Re: New, improved cabinet back
Post by: electra225 on September 10, 2017, 10:44:28 AM
We have played the Concert Grand at least a day with the new back on it.  It will run for eight hours and the bottom of the MPX is barely warm.  Previously, one could fry eggs on it after about three hours.  The amplifier power transformers barely get warm now.  They previously ran pretty hot, too hot to touch.  There is still some heat in the changer compartment, but nothing like there was.  My wife contends that the bass response is better than it was.  I think she is "hearing things."
Title: Re: New, improved cabinet back
Post by: Bill on September 11, 2017, 09:32:15 AM
Congrats on the new back and that it is a success.  It's always a good feeling when a project is complete and that it works the way one had hoped.  Which by the way does not always happen for me.

Bill
Title: Re: New, improved cabinet back
Post by: electra225 on September 16, 2017, 07:38:07 PM
The problem with the Multiplex adapter turned out to be a bad connection on the input cable from the MPX to the tuner.  While I was in there, I exchanged the MPX in there currently with a 7003-00 "short cable" version that I sourced courtesy of a member on another forum.  It is still the two-tube version.  I have some pictures for reference that I will post below.  That system is now working like it should.  I have the back on and all the screws in it.  That means something will break, necessitating my removing all those blasted screws again! 

And, finally, my able assistant, Bentley.  He is the one with the white hair.   ;)

While I'm thinking of it, is it possible for some enterprising member to reproduce the model number/serial number stickers with the correct font?  All mine are turning brown and yukky and I'm not computer savvy enough to reproduce them.  I'll bet I'm not the only member on here who would appreciate a nice, new sticker for his Magnavox cabinet.  I'm not a photographer, either.  So forgive my poor photography on a couple of those pictures.  I could not get the light right........