[GreenKeys] Flesher TU-170 Loop Key Transistor

[Harold Hallikainen]

Did not realize there was an internal loop supply! Missed that as I was
reviewing the manual. I am temped to put a clamping zener across the
printer connection to the TU-170.

Thanks!

Harold

> I see you mention the 152590 loop supply, you realize that the TU-170 has
> an internal loop supply?
>
> I'd better shut up, half asleep and making mistakes.
>
> John, W9DDD
>
>
>> On Oct 30, 2020, at 11:02 PM, hwhall at compuserve.com wrote:
>>
>> I've built keyers using that transistor and always had an RC snubber
>> across them.
>>
>> Wayne
>> WB4OGM
>>
>> -----Original Message-----
>> From: Harold Hallikainen <harold at mai.hallikainen.org>
>> To: Green Keys <greenkeys at mailman.qth.net>
>> Sent: Fri, Oct 30, 2020 8:20 pm
>> Subject: [GreenKeys] Flesher TU-170 Loop Key Transistor
>>
>>
>> I'm looking at the manual for the TU-170 and see that it keys the loop
>> with an MJE340 which has a maximum Vce of 300 V. 152950 loop supply has
>> a
>> loaded output voltage of 125 V. Can the MJE340 take the inductive spike
>> when it opens the loop, or should a clamp be added?
>>
>> Thanks!
>>
>> Harold
>>
>>
>>
>> --
>> FCC Rules Updated Daily at http://www.hallikainen.com
>> Not sent from an iPhone.
>>
>>
>>
>> --
>> http://w6iwi.org
>> ______________________________________________________________
>> GreenKeys mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:GreenKeys at mailman.qth.net
>>
>> >>> Jordan Spencer Cunningham's GreenKeys Search Tool:
>> https://teletype.net/gksearch
>> >>> 2002-to-present greenkeys archive:
>> http://mailman.qth.net/pipermail/greenkeys/
>> >>> 1998-to-2001 greenkeys archive:
>> http://mailman.qth.net/archive/greenkeys/greenkeys.html
>> >>> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:
>> http://comcents.com/tty/greenkeyssearch.html
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to hwhall at compuserve.com
>> ______________________________________________________________
>> GreenKeys mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:GreenKeys at mailman.qth.net
>>
>>>>> Jordan Spencer Cunningham's GreenKeys Search Tool:
>>>>> https://teletype.net/gksearch
>>>>> 2002-to-present greenkeys archive:
>>>>> http://mailman.qth.net/pipermail/greenkeys/
>>>>> 1998-to-2001 greenkeys archive:
>>>>> http://mailman.qth.net/archive/greenkeys/greenkeys.html
>>>>> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:
>>>>> http://comcents.com/tty/greenkeyssearch.html
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to w9ddd at tapr.org
> ______________________________________________________________
> GreenKeys mailing list
> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:GreenKeys at mailman.qth.net
>
>>>> Jordan Spencer Cunningham's GreenKeys Search Tool:
>>>> https://teletype.net/gksearch
>>>> 2002-to-present greenkeys archive:
>>>> http://mailman.qth.net/pipermail/greenkeys/
>>>> 1998-to-2001 greenkeys archive:
>>>> http://mailman.qth.net/archive/greenkeys/greenkeys.html
>>>> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:
>>>> http://comcents.com/tty/greenkeyssearch.html
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to harold at w6iwi.org


-- 
FCC Rules Updated Daily at http://www.hallikainen.com
Not sent from an iPhone.