It's alive! Experimental Delco Car TV

[Bobby Dip]

I finally decided it was time to turn off the scope, and try a picture tube. I bought a 5AXP4 test tube on eBay. (To my great surprise, it's labeled "GM Delco" I worked at Delco Radio for 32 years, and never heard of Delco manufacturing any tubes of any sort. Back in the 50's, Delco rebadged a few TVs and sold them through United Motors. BUT, why would GM/Delco bother to rebadge a low volume test CRT ??????)

When I first tried the 5AXP4, there was nothing on the screen, no line, no dot, nothing. The HV, G2, G1, and cathode voltages checked OK. and there was video on the cathode. Then I noticed that the 5AXP4 data sheet said the tube is self focusing (electrostatic). I also noticed there was a magnetic ring on the yoke that was removable. So, I removed it and voila, there was a picture! I guess magnetic focusing and electrostatic focusing don't play together well.

I have yet to try out the 8AP4 that I bought for this set. (This set came out of the company vault with no picture tube, power supply, or documentation.)
Actually, the 8AP4 was just a guess. It will fit physically, but will it work? One thing that bothers me is that the 8AP4 has no G2, but the socket has 300V for the G2 pin. At least I know the set will work with some tube, now!









Bob D.

[Dave A]

Bobby, congrats on getting this mystery thing going no matter what the tube! The chassis looks like a true under-dash installation but what was it used in? My '59 Cad does not have this option and my grandfathers '56 Chev did not have it either.

[Paul Knaack]

KOOL, Glad to see you got it going. I had been following your thread and was wondering if you got it working. Excellent.

[Phil Nelson]

Wow! That's a nice picture.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

[Spinning Head]

As you well know, you could very likely have the only functioning set of this design. Great work! The GM Delco CRT is even more fitting.

[Bobby Dip]

Originally Posted by Dave A

Bobby, congrats on getting this mystery thing going no matter what the tube! The chassis looks like a true under-dash installation but what was it used in? My '59 Cad does not have this option and my grandfathers '56 Chev did not have it either.

This set never went into production. AFAIK, the only GM cars that had a TV were concept/show cars. The chassis was designed to fit between the two front seats. The picture tube faced the back seat, and angled upwards for viewing by the rear seat passengers.

I don't think any car manufacturer ever came out with an OEM TV. The reception problems (mostly mulitpath) were insurmountable. I wonder if it would work better now that the TV signal is digital

Bob D.

[Sandy G]

I have a book "Cadillac-The Complete History" that dates from '79 or so. There is a picture of a model playing w/a likely 8-9" TV set as installed in a Caddy show car, circa 1956. It is mounted in the front seat backs/partition. Over the air TV reception in a moving vehicle is an exercise in futility/frustration... I tried it w/a Sony Watchman, & the only DECENT picture I got was of WSJK TV, Channel 2, the local PBS outlet, when the transmitting tower was in plain view..

[Phil Nelson]

Yes, I remember trying to watch TV in a moving vehicle with a Watchman and one other handheld TV once upon a time. Exercise in futility is an apt description.

Phil Nelson

[jr_tech]

Originally Posted by Bobby Dip

I don't think any car manufacturer ever came out with an OEM TV. The reception problems (mostly mulitpath) were insurmountable. I wonder if it would work better now that the TV signal is digital

Nope! ATSC will not work in a moving vehicle. There is an additional stream that some ATSC transmitters can use called "Mobile/Handheld" or M/H that will work in a mobile application, but so far, few broadcasters are using it.

Great job on the TV! Hope to see it working with the 8AP4!

jr

Fantastic work and a great picture!

At the time a lot of auto parts sold a lot of other items such as radios and TV's, and United Service distributed them, similar to Firestone and Western Auto. I suppose Delco thought some of their dealers would get into repair and ordered up a batch of 5AXP4's to distribute to them.

I found a 1950 Billboard article that said Delco executives were looking at getting into making their own sets instead of re-branding others. Obviously, they decided not to. It does seem that it might have worked if they had combined them with Fridgidaire appliances.

[bigaudioal]

Really neat set. Congrats on getting it going!

[Electronic M]

Originally Posted by Phil Nelson

Yes, I remember trying to watch TV in a moving vehicle with a Watchman and one other handheld TV once upon a time. Exercise in futility is an apt description.

Phil Nelson

That's Odd. I have used a portable set on road trips a few times before NTSC went away, and while a snow free picture was difficult to achieve it was quite watchable....I got much better results with a portable set while riding a bicycle. The major difference is that using a portable set in a car with no outside antenna is going to kill the station signal strength because the metal auto body acts as a Faraday cage and eats most incoming signal that would otherwise reach the antenna of a portable inside it.

[David Roper]

I can also report pretty fair experience with in-car TV. First a JVC 3050 then a tiny Sanyo both were capable of good reception anywhere within what could reasonably considered a station's fringe. You just knew going in that you were in for periodic dialing around on an extended trip.

Later on there was a little outside antenna that would stick through a window, but I don't recall it giving substantially better results than the more adjustable whips. That gadget may even have been given up on, it's just too long back to recall.

[jr_tech]

YMMV, I remember the quality of reception of analog TV in a moving vehicle being *very* dependant on terrain, distance to the transmitter, frequency of the channel and willingness to accept a degree of flicker and instability. Multipath was the real killer here... large buildings, hills and wet trees were major problems. Out in the "flatlands" with near line of sight to the transmitter tower, reception *could* be pretty decent.
jr

[dieseljeep]

Originally Posted by egrand

Fantastic work and a great picture!

At the time a lot of auto parts sold a lot of other items such as radios and TV's, and United Service distributed them, similar to Firestone and Western Auto. I suppose Delco thought some of their dealers would get into repair and ordered up a batch of 5AXP4's to distribute to them.

I found a 1950 Billboard article that said Delco executives were looking at getting into making their own sets instead of re-branding others. Obviously, they decided not to. It does seem that it might have worked if they had combined them with Fridgidaire appliances.

I bought a lot of tubes branded GM Delco. They were sold at the distributors that handled parts for Delco car radios. They were RCA sourced. The test CRT was probably bought from those firms.