Forums :: NEW! Web Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives
Support This Site: Contributors :: Advertise


It is currently Oct Thu 29, 2020 11:18 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 23 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: Is this a HP 200 precursor ?
PostPosted: Jul Sun 14, 2013 4:19 pm 
Member

Joined: May Sat 22, 2010 4:42 pm
Posts: 2987
Just looking around eBay and I found this unusual its:

http://www.ebay.com/itm/Hewlett-Packard ... 20cef5d057

It kinda looks a whole lot like a HP-200 audio oscillator, but a more primitive version.

The conventional stories all say that the 200 was the first product, but this one looks like it might have preceded the 200.

It has the big tuning capacitor, the night-light, so it's the same circuit design, so it's probably from HP, and everything looks less refined, with the asymettrical panel layout, the tight confines, and the under-chassis layout.

And it doesn't have a model tag.

Could this have been a prototype?


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Jul Sun 14, 2013 5:04 pm 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 2220
Location: Seattle, WA, USA
That is cool! I kinda doubt that it is a 200 prototype, more likely a clone, but who knows. You should repeat your post on the HP / Agilent Yahoo group:

http://tech.groups.yahoo.com/group/hp_a ... equipment/

There are some real experts there that may be able to ID this thing.

-Matthew

_________________
If it ain't broken, you’re not trying hard enough...


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Jul Sun 14, 2013 5:08 pm 
Member

Joined: Feb Wed 25, 2009 4:06 pm
Posts: 1483
Location: Morristown, N.J.
It sure looks like a prototype to me and without question it was made by HP.

The seller should send some photos to HP and see if they might want to buy it.

Pete AI2v

_________________
Pete AI2V

"It's always darkest before it's pitch black"


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Jul Sun 14, 2013 5:45 pm 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 2220
Location: Seattle, WA, USA
I just bought it! I will post lots more pictures when I get it.

-Matthew

_________________
If it ain't broken, you’re not trying hard enough...


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Jul Sun 14, 2013 7:28 pm 
Member
User avatar

Joined: May Wed 18, 2011 2:40 am
Posts: 5016
Location: Littleton, MA
The frequency range matches the 200B. The 200A went up to 35 kc; this one goes to 20 kc like the 200B. The tube and transformer and inductor complement at first glance seem to match that of a 200A or 200B, but the physical layout is very different. The frequency scale is attached to the panel, rather than to the knob as in the 200B. This means the tuning capacitor has to increase in value when turned counter-clockwise, whereas the 200B capacitor increases in value when turned clockwise. I don't see any large paper capacitors in this unit (C4 and C10 in the 200B); it must use non-polarized or back-to-back electrolytics instead.

The engraved front panel, laced wiring, and general construction suggest that it's not a home-brew, but the asymmetrical panel layout suggests that it may be a home-brew, though a very well done one. There are two holes in the front panel at the upper left that suggest mounting holes for a military-style nameplate. My guess is that it is a 200B clone, perhaps from a military contract.

_________________
Steve Byan https://www.byan-roper.org/steve/steve-at-play/


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Jul Sun 14, 2013 7:46 pm 
Member

Joined: Sep Thu 23, 2010 6:37 am
Posts: 12437
Location: Powell River BC Canada
I don't see front terminals so it might be an oscillator for a radio station to
provide tone for studio or master control use.

_________________
de
VE7ASO VE7ZSO
Amateur Radio Literacy Club. May we help you read better.
Steve Dow
ve7aso@rac.ca


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Jul Sun 14, 2013 9:21 pm 
Member

Joined: Jun Sun 23, 2013 9:03 pm
Posts: 483
Location: Canandaigua, NY
Might be a clone, might be a custom done by the factory or something for the mil. The 200 was also available in rack mount, but with a different layout than this one. Curious what you find when you get it.


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Jul Sun 14, 2013 10:27 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 25381
Location: Pocasset, Cape Cod, MA
The date codes on the parts and tubes will tell a lot, but in my opinion it's a clone made during the war or later by a college lab or small company.


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Jul Sun 14, 2013 11:22 pm 
Member

Joined: Sep Thu 23, 2010 6:37 am
Posts: 12437
Location: Powell River BC Canada
When did they stop insisting that common tubes could be not be in telephone, motion
picture, or radio broadcasting equipment without special licence?

My 200 B has a patent number plate on the back saying that the circuit is
licensed by Western Electric and RCA.

The patent numbers are: 2 173 427 resistance oscillator with no coil invented by HH Scott
for General Radio. 1939


2 288 672 same as above with lightbulb and far more sophisticated circuit invented by Winiun K. Hewlett for HP 1942.

I assume the Western Electric and RCA permissions are for the tube circuits not
being in a radio ?

_________________
de
VE7ASO VE7ZSO
Amateur Radio Literacy Club. May we help you read better.
Steve Dow
ve7aso@rac.ca


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Jul Mon 15, 2013 12:36 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 25381
Location: Pocasset, Cape Cod, MA
If you haven't seen it, there's a page in Tube Testers and Classic Electronic Test Gear on HP, GR, Hewlett, Scott and the R-C oscillator.

Quote:
When did they stop insisting that common tubes could be not be in telephone, motion
picture, or radio broadcasting equipment without special license?
Probably when the patents ran out.


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Jul Mon 15, 2013 2:01 am 
Member

Joined: Sep Thu 23, 2010 6:37 am
Posts: 12437
Location: Powell River BC Canada
Thanks, I just bought your book a couple of months ago. Too new to read it, I guess. :D

_________________
de
VE7ASO VE7ZSO
Amateur Radio Literacy Club. May we help you read better.
Steve Dow
ve7aso@rac.ca


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Jul Mon 15, 2013 2:46 am 
Member
User avatar

Joined: Jun Wed 08, 2011 2:33 am
Posts: 10891
Location: Ohio 45177
I have been parting out some HP stuff from the dumpster. Got a 200CD that is going to be cannibalised next. Transformers and knobs and the big cap! Wheee!

_________________
Reddy Kilowatt says; You smell smoke? Sorry about that!


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Jul Mon 15, 2013 4:21 am 
Member

Joined: Sep Thu 23, 2010 6:37 am
Posts: 12437
Location: Powell River BC Canada
wazz wrote:
I have been parting out some HP stuff from the dumpster. Got a 200CD that is going to be cannibalised next. Transformers and knobs and the big cap! Wheee!



The tuning cap would make a wing-ding of an old tube TRF, using 24-A tubes
of course.

_________________
de
VE7ASO VE7ZSO
Amateur Radio Literacy Club. May we help you read better.
Steve Dow
ve7aso@rac.ca


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Jul Mon 15, 2013 8:27 pm 
Member

Joined: Jun Fri 19, 2009 6:34 pm
Posts: 10032
Location: Long Island NY
HP has Bill Hewlett's original prototype oscillator, which was his Stanford University thesis project, in its archive. So no, the unit that was on eBay is not the prototype. In fact, I had an ex-US Navy 205A that was constructed identically to the eBay unit, except it was bigger. (The 205A has a push-pull 6L6 output stage to deliver five watts, and an output level meter). As with the 205A, I'd think this 200B was built for the military during WW-2. The holes in the upper left corner of the front panel suggest that it once had a nameplate, now gone. Taking military nameplates off used to be quite common when equipment was "de-milled."

_________________
"Hell, there are no rules here--we're trying to accomplish something!"

Thomas A. Edison


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Jul Tue 16, 2013 12:35 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 25381
Location: Pocasset, Cape Cod, MA
Not to mention that it uses potted mil-spec chokes and transformers.


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Aug Sat 31, 2013 9:36 pm 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 2220
Location: Seattle, WA, USA
Sorry for the long delay in not getting back to you guys about this. I have had a lot of other things to get done this summer so this unit has just been sitting. Anyway, I received it without damage and have carefully examined it. Here are my conclusions:

1) It is certainly a factory unit. Although some of the wiring looks hackish, that is all later repair work. The original design was clean and professional.

2) There are absolutely no marks on any of the parts to indicate the original manufacturer. All components appear to be generic off-the-shelf type except the chassis, front panel, and a terminal board under the chassis.

3) There are two holes on the front panel from where a nameplate was once mounted. From the marks on the paint, the nameplate was a rectangle 3-3/8 long and 7/8 tall with holes spaced 3-3/16 apart.

4) There was a second square nameplate mounted on the right side, about 1" x 2" mounted by four screws in the corners. It has been removed and number '56' written in grease pencil in its place.

5) All the tubes with date codes are from 1948, but only one is a mill-spec (JAN) type.

6) All parts are screwed to the chassis (no rivets)

7) Holes indicate that there was once a lid over the chassis.

8) There is an unmarked holes for an unknown connector in the back of the unit which I suspect may have been a military style power connector - the brown lamp-cord on it now does not look original.

9) Unless someone might know if there are date codes on capacitors, I can find no original parts with readable date codes on them.

10) Marks on the front panel indicate that it was once rack mounted.

My hunch is that this was a piece of NAVY gear made during or just after the war. After the war it was decommissioned and had its tags removed before being sold to a hobbyist or service shop which modified it by adding a standard power cord and then used and maintained it for many years, (crudely) replacing components as needed.

Below are pictures of the details.

Top of chassis:
Image

Right side:
Image

Left side:
Image

Back:
Image

Filter capacitor detail:
Image

Power cord detail:
Image

Transformer detail:
Image

Bottom:
Image

Front:
Image

Nameplate detail:
Image

Datecode on tube:
Image

-Matthew

_________________
If it ain't broken, you’re not trying hard enough...


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Aug Sat 31, 2013 10:23 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 31285
Location: Maryland 20709, USA
Hi Matthew,

Neat item.

I believe the large round hole with two lateral mounting holes originally held a male twist-lock connector.
These were quite common in industrial equipment, since they would not fall out accidentally.

Military MS-series connectors have a square mounting flange with four screw holes.

My guess is it's a military procurement, copying the HP 200 oscillator but made by a different company.

- Leigh

_________________
73 de W3NLB
http://www.AtwaterKent.info
Click "Grebe Stuff" for Synchrophase info


Last edited by Leigh on Sep Sun 01, 2013 12:54 am, edited 1 time in total.

Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Sep Sun 01, 2013 12:46 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 25381
Location: Pocasset, Cape Cod, MA
Quote:
4) There was a second square nameplate mounted on the right side, about 1" x 2" mounted by four screws in the corners. It has been removed and number '56' written in grease pencil in its place.
I imagine the 56 was there first, while the serial-number plates were being ordered.


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Sep Sun 01, 2013 5:50 am 
Member
User avatar

Joined: Jun Sun 14, 2009 10:44 pm
Posts: 466
Most interesting...What's the tube line-up?


Top
 Profile  
 
 Post subject: Re: Is this a HP 200 precursor ?
PostPosted: Sep Mon 02, 2013 1:01 am 
Member

Joined: Jun Fri 19, 2009 6:34 pm
Posts: 10032
Location: Long Island NY
Hard to say what the origins of this unit were. The terminal board construction and the holes drilled around the tube sockets for ventillation are definitely details you can find on most 1940s and '50s HP instruments. But the lack of a bottom cover or even the means to attach one is something HP would not have overlooked.

From the looks of the terminal board, this unit was in operation for years. Perhaps it was installed out in the transmitter shack of some radio or TV station for overnight transmitter testing.

_________________
"Hell, there are no rules here--we're trying to accomplish something!"

Thomas A. Edison


Top
 Profile  
 
Post New Topic Post Reply  [ 23 posts ]  Go to page 1, 2  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: Barry H Bennett and 33 guests



Search for:
Jump to:  


































-->


Privacy Policy :: Powered by phpBB