Topics

Curve tracer as a power supply

DW
 

I have encountered a situation which I have a Symetrix SX204 headphone distribution amplifier that needs 16VAC to operate but I have no such such supply that will offer that...

However I have a 577 curve tracer. My initial thoughts is to set the collector polarity to AC and the voltage to 25V and the series resistance 1 ohm or below. This headphone amplifier only takes 500 mA it claims to run it along with a 1 amp slow blow fuse. I think I should be fine but just incase I would like to get a second opinion here, thanks

Bill Perkins
 

I dunno, I'm thinkin' I'd be taping a single turn along the four walls in the room where I keep my Tesla coil; oughta work but I'd have sit in another room a' course. :-)

Bill @ PEARL, Inc.

I have encountered a situation which I have a Symetrix SX204 headphone distribution amplifier that needs 16VAC to operate but I have no such such supply that will offer that...
However I have a 577 curve tracer. My initial thoughts is to set the collector polarity to AC and the voltage to 25V and the series resistance 1 ohm or below. This headphone amplifier only takes 500 mA it claims to run it along with a 1 amp slow blow fuse. I think I should be fine but just incase I would like to get a second opinion here, thanks

Harvey White
 

Might work, might not.

https://www.amazon.com/s?k=16+vac+power+adapter&crid=2LME6SELGCA7L&sprefix=16+VAC+%2Caps%2C161&ref=nb_sb_ss_i_4_7

adaptor, under 20 dollars.

Fixing 577 curve tracer?

Priceless.

The supply is just a transformer.  12 volts AC CT, dual winding gives you about 18 volts.

16 volt supplies are apparently "out there".

If there's no transformer in the beast, you might just be able to run it off DC.  IF (and I've seen the reason why not) there's a single polarity supply running, say, a 12 to 15 volt bulk supply. However, the AC may also be used to provide a negative supply that a DC connection won't.

and (FWIW), don't try to run 24 volt AC surveillance cameras off DC, there *is* a transformer in there.

Harvey

On 7/12/2020 10:29 PM, DW wrote:
I have encountered a situation which I have a Symetrix SX204 headphone distribution amplifier that needs 16VAC to operate but I have no such such supply that will offer that...

However I have a 577 curve tracer. My initial thoughts is to set the collector polarity to AC and the voltage to 25V and the series resistance 1 ohm or below. This headphone amplifier only takes 500 mA it claims to run it along with a 1 amp slow blow fuse. I think I should be fine but just incase I would like to get a second opinion here, thanks


saipan59 (Pete)
 

1) Go to WalMart, buy the cheapest gadget that has a wal-wart marked "12VAC". Connect it to your headphone amp.

2) Then go to a flea market, buy an old transistor radio, remove a transistor from it, and plug it into your 577.

<grin>
Pete

DW
 

This headphone amplifier I am attempting to power up I am not the owner but simply doing a repair and then returning it.

Another thought is a autotransformer with a isolation transformer should I get another AC device similar to this I can adjust to the voltage needed should it be different. Though best to try to get the wall adapter to avoid this trouble.

DW
 

"Thought best to try to get a wall adapter to avoid this this trouble" I forgot to add "That originally powered the device"

Ed Breya
 

These CT's collector supplies are basically variacs and ranging transformers, with some selected ballast/current limiting, so of course you can run small AC loads. I assume that this is just for servicing the DUT temporarily. If anyone would consider this as a permanent or long-term solution, I would give this standard admonition:

It's an extreme waste of precious instrument (especially CRT) life. I've often used CTs for just such purpose, but only for quick checks and diagnosing problems. For permanent, long-term running of things, just rig up simple, suitable supplies, and save the CT for when you really need it.

So anyway, it seems this is just a repair project, so don't bother with getting a wallwart just for fixing the device. Your original plan is sound, and a fine use for the 577. It will give you much control over it, and insight into what's going on inside, which is the point of using a CT in the first place.

Your OP didn't explicitly say "temporary," which is probably why so many responded with the common-sense "don't waste a CT on this" approach.

Ed

Ed Breya
 

One last thing - in your particular case, remember that the AC out from the CT is earth (chassis) ground-referenced, so depending on the internals of the DUT, you'll need to be aware and careful of what ground/common is what. At least with a wallwart, the AC winding is usually floating, so it matters less.

Ed

Greg Muir
 

I personally use a 500 kW diesel generator to power my headphone wall wart. Kind of noisy but the headphones have a good acoustical seal to my head.

Greg

Dale H. Cook
 

On 7/12/2020 10:29 PM, DW wrote:

I have encountered a situation which I have a Symetrix SX204 headphone distribution amplifier that needs 16VAC to operate but I have no such such supply that will offer that...
However I have a 577 curve tracer.
You would be much better off to sell the 577 to someone who wants and needs a curve tracer and buy a wall wart for the SX204. Using the 577 to power the SX204 is like using a Shelby Cobra to provide the 12 VDC voltage needed to charge your laptop battery
--
Dale H. Cook, Radio Contract Engineer, Roanoke/Lynchburg, VA
https://plymouthcolony.net/starcityeng/index.html

Dale H. Cook
 

On 7/13/2020 12:52 AM, DW wrote:

This headphone amplifier I am attempting to power up I am not the owner but simply doing a repair and then returning it.
I have spent 50 years repairing broadcast equipment. I strongly suggest that you pass the SX204 on to someone with a reasonably well equipped shop, including variable AC and DC supplies, rather than attempt to repair it yourself.
--
Dale H. Cook, Radio Contract Engineer, Roanoke/Lynchburg, VA
https://plymouthcolony.net/starcityeng/index.html

Colin Herbert
 

Or, for those with no idea what a Shelby Cobra is, or can do, a Bugatti Veyron or Aston Martin Superleggera (or even a Bentley Continental).
Colin.
(Sorry for the excessive automobile references when they have very little to do with any kind of oscilloscopes).

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dale H. Cook
Sent: 13 July 2020 14:31
To: TekScopes@groups.io
Subject: Re: [TekScopes] Curve tracer as a power supply

On 7/12/2020 10:29 PM, DW wrote:

I have encountered a situation which I have a Symetrix SX204 headphone distribution amplifier that needs 16VAC to operate but I have no such such supply that will offer that...

However I have a 577 curve tracer.
You would be much better off to sell the 577 to someone who wants and
needs a curve tracer and buy a wall wart for the SX204. Using the 577 to
power the SX204 is like using a Shelby Cobra to provide the 12 VDC
voltage needed to charge your laptop battery
--
Dale H. Cook, Radio Contract Engineer, Roanoke/Lynchburg, VA
https://plymouthcolony.net/starcityeng/index.html

Vince Vielhaber
 

Since it's in for repair it's best to have its own wall wart since the problem could be there.

Rather than using your curve tracer to power it, I think you may have the right idea with a variac and a transformer. Get a 24-36 volt transformer (ebay or MPJA) and use the variac to lower the voltage to what you need.

Vince.

On 07/13/2020 12:52 AM, DW wrote:
This headphone amplifier I am attempting to power up I am not the owner but simply doing a repair and then returning it.

Another thought is a autotransformer with a isolation transformer should I get another AC device similar to this I can adjust to the voltage needed should it be different. Though best to try to get the wall adapter to avoid this trouble.


DW
 

My interpretation so far to use a curve tracer in this application is like using a flash light to hammer in a nail. Though the flash light might be heavy and made out of metal and could work, it is astoundingly dumb and embarrassing and the person probably needs to get help.

Although I am embarrassed for asking such a question, this topic appears to have become a public announcement alerting any other potential curve tracer owners who might be on the fence on doing this to think twice but too embarrassed to ask such a question as I have.

I value the 577 although such a question might suggest otherwise (use it to charge car batteries), its primary use is testing MJ15015G and 2N5038G transistors out of a Harris MW1A transmitter as well as other various transistors and diodes at least

Leon Robinson
 

To tie this to tekscopes anyone who can afford a car like that csn afford any tek scope that they want.


Sent from K5JLR

-------- Original message --------
From: "Colin Herbert via groups.io" <colingherbert=blueyonder.co.uk@groups.io>
Date: 07/13/2020 8:51 AM (GMT-06:00)
To: TekScopes@groups.io
Subject: Re: [TekScopes] Curve tracer as a power supply

Or, for those with no idea what a Shelby Cobra is, or can do, a Bugatti Veyron or Aston Martin Superleggera (or even a Bentley Continental).
Colin.
(Sorry for the excessive automobile references when they have very little to do with any kind of oscilloscopes).

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dale H. Cook
Sent: 13 July 2020 14:31
To: TekScopes@groups.io
Subject: Re: [TekScopes] Curve tracer as a power supply

On 7/12/2020 10:29 PM, DW wrote:

I have encountered a situation which I have a Symetrix SX204 headphone distribution amplifier that needs 16VAC to operate but I have no such such supply that will offer that...

However I have a 577 curve tracer.
You would be much better off to sell the 577 to someone who wants and
needs a curve tracer and buy a wall wart for the SX204. Using the 577 to
power the SX204 is like using a Shelby Cobra to provide the 12 VDC
voltage needed to charge your laptop battery
--
Dale H. Cook, Radio Contract Engineer, Roanoke/Lynchburg, VA
https://plymouthcolony.net/starcityeng/index.html