Delmonico 4T-20U

[bandersen]

I stumbled across one of this on ebay recently for $30. I'd never seen one before and didn't know anything about them. A little web searching revealed it was made by JVC around 1964 and ran on 9 rechargable D cells or an external 12 VDC source.

I ended up the only bidder at $29.95

Service info seems to be scarce. All I could find was a schematic in Sams 987-SED

It arrived inside a vintage makeup case which actually did a good job protecting it.


Here are some photos for the original ebay listing. FOr sure it's dirty and the leather case has seen better days but is mostly all there.

I think I'm only missing a knob on the external power supply / battery charger.










Here it is up on the workbench ready for a checkout and power up test. More soon...

[AlanInSitges]

I can't wait to see what's in there

Solid state TVs of that era give me the heeby-jeebies because everything is so tiny and cramped, wiring is convoluted, and nothing is marked.

[bandersen]

So far I've only looked inside the power supply but I see what you mean!

The neon power light lit up but no voltage out in either AC or charge modes.
There are several transistors crammed under a heatsink with a mess of wires going to them. Nothing is labeled.


Luckily, I fairly quickly isolated the problem to the mode switch. After several round of DeOxit and working the switch many times, I'm still not getting good continuity.



So I temporarily bypassed it and got about 12 VDC out. I hooked up the set and after a bit of tinkering got some reception. OK sound but couldn't get the horizontal to lock. Adjusting the internal Hor Freq control helped but it's just too far off to sync.

Also all the controls are very dirty - especially the sound.

First glimmer of life.


The closest I could get to a locked image.

[Crist Rigott]

Cool project.

[bandersen]

I put a copy of the schematic here: https://drive.google.com/open?id=1DH..._XnpNnO8-aA0mj

I'm struggling to get this open. I can't get the four small knobs off!
I'm thinking of making a customer knob puller by modifying a metal fork.


I did manage to get the underside open though.
I wanted to get a look before I place an order for new caps to make sure they'd fit.
There is some corrosion. Perhaps a consequence of the batteries or maybe just moisture and age.






It's looking better after a little cleaning. I really need to get behind that safety glass and clean of some crud.

[Sandy G]

Got one YEARS ago, dead as a stone. Took it to Terry, he said the Flyback was toast, so that was that. Too bad, its a cyoot widdle bugger... I think it came w/the leather case, but that went away a LONG time ago. It was in pretty bad shape, IIRC.

[Electronic M]

Those 4 knobs might have set screws in the sunken centers... double check before ripping up them off.

[bandersen]

Yep, good call. I will check tonight. A tragedy may have been averted

[trinescope]

They do have slot head screws in the center. The controls look like transistor radio volume controls with the short double D shaft and threaded center.

[bandersen]

Success! Thanks for the tip

Of course, I immediately dropped one of the tiny screws. Luckily, it didn't take too long to find....





Now, I can finally clean the screen.


Here are some more shots of the insides for your viewing pleasure. Looks like a delight to service :P

[Mr Hoover]

Looking at the circuit I see it uses quite a number of 2SA 70 transistors in the IF stages, they do suffer from tin whisker
disease.. They're the larger diameter transistors in your pictures.
They have a fourth screen leadout which
also goes to the can.Physically
identical to the British Mullard
AF114,AF117 etc series which
had bad tin whisker disease
also.Symptoms can be intermittent
and tapping the transistor can make it
work sometimes.
I Had a 5"Sony which used those in the
IF's also,think a later version IF board used
different transistors.

[AlanInSitges]

If that's anything like my circa-1968 Sony, about half of the wires that are soldered to various places on the bottom of the PCBs will break off as soon as you move one of the boards. Take lots of closeup high-res pics of both sides so you can put them back together.

I've got one on my Sony that I can't figure out where it goes.

[Telecolor 3007]

Whoa, what a nice set. I don't know why, but it makes me feel nostalgic.
In Romania I think these where the smallest portable sets sold before 1990: http://rw6ase.narod.ru/00/twcb/elektronika_wl100.html

But in the '60's there where rechargable R20 (D) batteries?

[Sandy G]

Saw those Romanian/Soviet sets all over Ebay.. Thought they were Cute, would LOVED to have had one, but getting one from Romania to NE Tennessee- Not a chance. It would be "Doodle Dust", if you got it at all. And then, likely it wouldn't work & try finding parts and/or documentation... Too bad, like I said, they sure are CUTE..

[bgadow]

I recently sold a newer Delmonico, maybe late 60's at the newest. When I was getting it ready I realized it still had batteries; they are Eveready rechargables but not D cells-they are as long as 3 D's in a row, made just for sets like this, 4.5v. Of course, you could use the D's as well. I saved them, though they have corrosion.