test-drb August 2004

test-drb@ccmp.vtda.org

283 participants
661 discussions

Gaps in the collection (was Re: rarest computers. )

by dwight.elvey＠amd.com

>From: "Geoffrey Thomas" <geoffreythomas(a)onetel.com> > >Just remembered - it was the "spontaflex" ,- it was Sir Douglas Hall and >there is a web page devoted to his circuits. >Geoff. > Hi A quick search shows that these are at: http://freespace.virgin.net/spontaflex.reflex/ From looking at some of the text, these are a combination of a reflex with some regenerative feedback to increase the Q of the tuning circuits. I suppose one could write programs to sing through such a receiver on their clasic computer. Later Dwight

19 years, 10 months

TRS-80 Model III and Holmes VID-80 Schematics / Technical Reference

by nbreeden2＠comcast.net

Hi, I'm looking for a Technical Reference manual / schematics for a TRS-80 Model III and the Holmes VID-80 add-on board. I've found a fair amount on the model I and 4 via Google however there seems to be nothing on the Model III. -Neil

19 years, 10 months

atc-510 simulator

by rdy4immediate＠sympatico.ca

I have picked up one of these ATC 510 also ... I have full set of docs for it, all maintenance books and tapes ... I don't recall seeing any charts for it .. but I have not got into all the boxes ... I would love to talk sims or real aviation some time . More than glad to share what I have ,I got this sim given to me from a school that wanted rid of it ... they say it does not work ... if fly's wrong .. but I am pretty sure that I can get it going ... I love to fart around with stuff like that, jeeps me out of trouble. Anyway drop me line if you like Mark Jones MSN messenger - clubwood(a)hotmail.com

19 years, 10 months

anyone ever shipped an NEC APC?

by SUPRDAVE＠aol.com

>I've got a monochrome NEC APC (dual 8" floppies) that >I was going to eBay, but it hovers right at that magic >70lb rate which seems to hit all kinds of shipping >issues with USPS (won't deliver it), UPS (big $$$ >surcharge), & FedEx (only deliver to a business >address, $$$). Seems by the time you factor in ship >costs it wouldn't be worth it unless someone was >really desperate. Fedex ground ships to home addresses you know. Price isnt too bad. You could also try Airborne/DHL or Emery/Menlo worldwide for ideas also. -- I am not willing to give up my liberties for the appearance of 'security'

19 years, 10 months

Help! TU81 Plus tape drive problems.

by pat＠computer-refuge.org

(I sent this from the wrong email address last night...oops!) So, I was hoping to find some sort of manual (any kind) for my TU-81+ via google, but have failed. So, my TU-81+ doesn't want to power up. I've found the "hidden" power switch under the cover that I've flipped back and forth a couple of times, I've made sure the 110/220V jumper was set properly (110V), and tried different power cords, all to no avail. (I've bypassed the power controller in the rack and directly hooked the drive to an outlet.) The power supply "sounds" like it's getting some power when I plug it in, as I hear a small arc, presumably charging up some capacitors. However, the fan doesn't start up, and none of the front panel lights. Does anyone have any suggestions of where to go next? (Tony? :) I could just start pulling it apart and going through it, but I prefer to have some direction before I do that. Pat -- Purdue University ITAP/RCS --- http://www.itap.purdue.edu/rcs/ The Computer Refuge --- http://computer-refuge.org

19 years, 10 months

Gaps in the collection (was Re: rarest computers. )

by dwight.elvey＠amd.com

Hi Reading the article by Sir Douglas Hall, he mentions making an adjustment to keep the positive feedback below the point of oscillation. This sure sounds like regenerative to me. Regenerative feedback was used quite often to increase the effective Q of circuits to increase selectivity. The article of May 1976 seems to indicate that this is how this circuit works. This makes sense. There are many, many ways to introduce regenerative feedback. One of the early ones was to place a variable coil in the plate circuit that was not coupled to the tuned input. The circuit worked by the parasitic capacitance of the triodes grid to plate. This can be done with a transistor as well. I remember when I was a kid, I had one of those 2 transistor reflex receivers made by GE ( wish I still had it ). I modified it to be regenerative and was able to greatly extend both range and selectivity. At night, I pulled in stations across the US. Dwight >From: "John Honniball" <coredump(a)gifford.co.uk> > >Geoffrey Thomas wrote: >> Yes, thanks - but the author had a special name for it - that's what I can't >> remember. > >Was it "regenerative"? Or is that a different type of circuit >altogether? See, for example: > > http://www.electronics-tutorials.com/receivers/regen-radio-receiver.htm > >-- >John Honniball >coredump(a)gifford.co.uk >

19 years, 10 months

corrected TU81 url

by aek＠spies.com

www.bitsavers.org/pdf/dec/magtape/tu81

19 years, 10 months

Help! TU81 Plus tape drive problems.

by aek＠spies.com

The TU81 diag pathfinder and tech manuals are up now on www.bitsavers.org/pdf/dec/magtape/tu78 The drive itself is an OEMed CDC Keystone, there are some docs for it under cdc/magtape.

19 years, 10 months

Gaps in the collection (was Re: rarest computers. )

by dwight.elvey＠amd.com

>From: "ben franchuk" <bfranchuk(a)jetnet.ab.ca> > >Geoffrey Thomas wrote: >> Reminds me of the old Radio Constructor designs where the designer made one >> transistor do both rf and af amplification. >> Can't remember his name - or what he called his designs. >> I'm sure he was knighted or something like that .... anybody ? >> - Sir Alec Douglas Hall ? was it ? >> Sounds too much like Alec Douglas Hume ! > >I have no idea who invented it since it was used every where, since the >humble >vacume tube ( valve) was invented. You can still buy or build them today. > >http://www.vcomp.co.uk/one_tube_1935/one_tube_1935.htm >http://schmarder.com/radios/tube/index.htm >Ben. > > Hi The circuit is called a reflex circuit. The second web page above shows a tube reflex circuit. Dwight

19 years, 10 months

Monroe-Matic CSA-10

by spm1960＠yahoo.com

Hey Chuck what would one of these things be worth. If it was in great operating condition? Where would a guy find out. MonroeMatic help __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

19 years, 10 months

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test-drb August 2004