Stevens Power Supply

[Tom]

Howdy all,

I have one of the early Stevens coil and condenser testers and the (heavy) power supply for it.  I replaced the rectifier in the power supply with a bridge rectifier and the output voltage is much higher than the intended 6V.  More like 18V.  I’m not sure it hasn’t been worked on before I got it.  Does anyone have any insight, diagrams, specifications, or advice that could help me get the output closer to the intended 6V?  Any help is appreciated.

Thanks,

Tom

[RICHARD A. WHITE]

While I have never seen a Stevens opened up, I have successfully used a 7.5 volt laptop power supply so the battery is never needed. I hated wanting to use the machine and find the battery was dead. Never again… The latest power supply I found has multiple options for output. I checked the output at Tomahawk, just because… 7.69 volts…. tester runs fabulously…I currently have another iron in the fire. Replacing the vibrators, on the Model 98, 98A and 9800 Mercotronics with a NE555 timer. I have the timer, I have the schematics just need to finish up a few other odds and ends to get that iron started..

I really need to retire….lol 330 ish working days till I am free!

Richard

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[JACQUES]

you can always try/ install an additional buck converter(s )to step down your new .. .18 v dc  to  a flat 6 v.

just pick/search  one with the expected amp drain  capacity normally used to drive the coils /condenser circuits

Valefod 6 Pack LM2596 DC to DC High Efficiency Voltage Regulator 3.2-35V to 1.25-30V Buck Converter DIY Power Supply Step Down Module : Amazon.ca: Tools & Home Improvement

a couple  (2) in paralll will get you 6 amps         3 will get you 9 amps

Joining AOMCI has priviledges 🙂

[mic57]

What type of rectifier did you replace? If it was Selenium you will need to add a dropping resistor sized for the current draw of the tester.

[RICHARD A. WHITE]

psssst……Laptop power supply..none of that other stuff needed…LOL

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[Tom]

Thanks for the responses.  I use a Makita 7.2 volt battery pack with the unit, it’s always worked well.  I just wanted to see about reparing the original unit.  T

 

[mic57]

I would put a 200 ohm  1 watt or something close resistor in series with the rectifier output. Either + or -. This should give you the voltage drop that you need. The early rectifiers pre mid 60s had high internal resistance compared with their silicon counterparts so an external resistor needs to be added when replacing them.

[Tubs]

RICHARD A. WHITE wrote:

While I have never seen a Stevens opened up, I have successfully used a 7.5 volt laptop power supply so the battery is never needed. I hated wanting to use the machine and find the battery was dead. Never again… The latest power supply I found has multiple options for output. I checked the output at Tomahawk, just because… 7.69 volts…. tester runs fabulously…I currently have another iron in the fire. Replacing the vibrators, on the Model 98, 98A and 9800 Mercotronics with a NE555 timer. I have the timer, I have the schematics just need to finish up a few other odds and ends to get that iron started..

I really need to retire….lol 330 ish working days till I am free!

Richard

“Free” that is the way I felt. I’m not much for remembering birthdays or anniversaries but I remember the last day I “had” to go to work. I knew several guys that didn’t want to retire because they didn’t think they would have anything to do. Not so much anymore but
there have been times when I thought about getting another job. One where you get to take breaks.

A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.

[JACQUES]

I knew several guys that didn’t want to retire because they didn’t think they would have anything to do.

ODD  I retired in 1997 after 30 years from a Telco  and followed up in 2007 retiring after 10 more years from a Cable co.   Been  coasting since 2007 ….never a dull moment…boating, fishing , painting, grass cutting snowblowing, 2 cottages, one  duplex , settling 3-4 estates one had 17 inheritors ( that was fun)….., caring for parents, aunt, and fixing up oldies….I now need to get rid of. 🙂

I collected more employer pension years than worked years !   Retiring twice were by best decisions.

 

 

Joining AOMCI has priviledges 🙂

[Author]

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