On 01/30/2014 04:16 PM, David wrote:

That will certainly work. Essentially you end up with a 2 port ROM
where only 1
port is available at any time. The address, data, and some of the
control lines
need to be multiplexed but that is not too difficult.

The same thing could be done with NVSRAM of one type or another or
even EEPROM.

I think there are some parallel access Flash memories which allow serial
programming via JTAG or something.

On 30 Jan 2014 11:55:08 -0800, you wrote:

I was going to whip a few boards up here at work as a proof of

concept (fortunate enough to have a CNC PCB milling machine on-site).
This article got me thinking about this problem again:
http://petenpaja.blogspot.ca/2014/01/vic-20-flash-memory-programmer-part-12.html
http://petenpaja.blogspot.ca/2014/01/vic-20-flash-memory-programmer-part-12.html

Why not just use a ATMEGA644 or even a Arduino Mega 2560 board?
Plenty of pins available so no multiplexing or shift register hacks needed.

The 556 dual-beam scope uses several 6M11 tubes (dual triode + pentode) as well as two 6GF5 tubes (beam power tube).  As far as I know, this is the only Tek scope that uses compactrons.

I've got a 556, and am looking for spares, both the 6M11, 6GF5, and the 8608 (used as the vertical output amps).

- John Atwood

 

I don't think any are used in the vertical amplifiers of either the 547 or 556 (which are nearly identical designs BTW), as these are all transistorized, except the first stage cathode follower which is a 12AT7.  The other tubes in the 547 are all single and dual sided tubes commonly used in several Tek scopes.

The 556 uses two 6M11 triple triodes, one in each sweep generator.

There is a novel miller integrator sweep generator design which can be implemented as a one tube design using a combination pentode-triode tube.  The Miller integrator itself is named a "Phastastitron" short for fantastic.  This cleaver design uses a single pentode for all of the functions of the sweep generator, including the cut off diodes and synchronization (rather than triggered operation.) The screens are used as additional grids in this design.  The triode serves as a cathode follower, to prevent the external load from altering the timing linearity.  Tek never used this design, as all Tek scopes have triggered rather than synchronized to the input signal.  It is useful if you want to design one of those “three tube scopes”.

 

- Steve

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I don't think any are used in the vertical amplifiers of either the 547 or 556 (which are nearly identical designs BTW), as these are all transistorized, except the first stage cathode follower which is a 12AT7.  The other tubes in the 547 are all single and dual sided tubes commonly used in several Tek scopes.

The 556 uses two 6M11 triple triodes, one in each sweep generator.

There is a novel miller integrator sweep generator design which can be implemented as a one tube design using a combination pentode-triode tube.  The Miller integrator itself is named a "Phastastitron" short for fantastic.  This cleaver design uses a single pentode for all of the functions of the sweep generator, including the cut off diodes and synchronization (rather than triggered operation.) The screens are used as additional grids in this design.  The triode serves as a cathode follower, to prevent the external load from altering the timing linearity.  Tek never used this design, as all Tek scopes have triggered rather than synchronized to the input signal.  It is useful if you want to design one of those “three tube scopes”.

- Steve

 

Howdy all,

  I'm going through my dad's collection of vacuum tubes and sorting through them.   I have a large number of used (pulls) "Compactron" type receiving tubes, and a smaller number of NIB Compactrons, as well as other tubes specific to TV sets of the day (1960's I presume).

   I'm thinking of unloading all of these cheaply on e-bay or some such thing, but before I do, are there any of them that I should save?  Are there any specific Compactron tubes that were used in later tube-era HP or Tek (or any other manufacturer's) instruments that I should keep in stock in the event I come across such an instrument some day?

  I'd rather get these into the hands of someone who will use them rather than store them.

This email is free from viruses and malware because avast! Antivirus protection is active.

 

That will certainly work. Essentially you end up with a 2 port ROM where only 1
port is available at any time. The address, data, and some of the control lines
need to be multiplexed but that is not too difficult.

The same thing could be done with NVSRAM of one type or another or even EEPROM.

I think there are some parallel access Flash memories which allow serial
programming via JTAG or something.

On 30 Jan 2014 11:55:08 -0800, you wrote:

>I was going to whip a few boards up here at work as a proof of concept (fortunate enough to have a CNC PCB milling machine on-site). This article got me thinking about this problem again: http://petenpaja.blogspot.ca/2014/01/vic-20-flash-memory-programmer-part-12.html http://petenpaja.blogspot.ca/2014/01/vic-20-flash-memory-programmer-part-12.html

 

Howdy all,

  I'm going through my dad's collection of vacuum tubes and sorting through them.   I have a large number of used (pulls) "Compactron" type receiving tubes, and a smaller number of NIB Compactrons, as well as other tubes specific to TV sets of the day (1960's I presume).

   I'm thinking of unloading all of these cheaply on e-bay or some such thing, but before I do, are there any of them that I should save?  Are there any specific Compactron tubes that were used in later tube-era HP or Tek (or any other manufacturer's) instruments that I should keep in stock in the event I come across such an instrument some day?

  I'd rather get these into the hands of someone who will use them rather than store them.

This email is free from viruses and malware because avast! Antivirus protection is active.