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Re: [Amps] Alpha 86

To: David Tenenbaum <dmt013@gmail.com>
Subject: Re: [Amps] Alpha 86
From: c miller <c_miller_1@hotmail.com>
Date: Tue, 8 Nov 2022 22:45:15 +0000
List-post: <mailto:amps@contesting.com>
Interesting that the board is stencilled lower.  If it still regularly blows 
the one particular fuse, then further investigation may be warranted.   If the 
fuse failure indicates simple overload ( not silvered or black fully or near 
fully ) then the fuse may have reached its end of life.  

Chris


Sent from my iPhone

> On Nov 8, 2022, at 17:05, David Tenenbaum <dmt013@gmail.com> wrote:
> 
> I think you have nailed it Chris: I had initially visually checked the slow 
> blow fuses and they looked fine, but an ohmmeter confirms one is not 
> conductive. My bad for not checking it with a meter first time around. 
> Embarrassing!
> 
> Two followups:
> 
> 1) The schematic says 1.5 amp slow blow, but the chassis stencil says 1.0 amp 
> SB. I am guessing it should not matter too much which I go with?
> 
> 2) Should I be looking at an underlying root cause before trying it with new 
> fuse? I guess worse that can happen is it blows again....
> 
> Thanks for the help, sorry for the rookie oversight!
> 
> David
> N1RO
> 
> 
> 
> 
>> On Nov 8, 2022, at 4:52 PM, c miller <c_miller_1@hotmail.com> wrote:
>> 
>> Not too odd really.  On 120v it is possible to run the initial startup cycle 
>> on just one of the two windings.  Then once the soft start circuit bypasses 
>> then both windings come into operation and unit preforms as intended.  
>> However, with either fuse F3 or F4, or resistor R6 or R7, in the soft start 
>> circuit being open, no power ever gets passed on to the transformer thus 
>> locking the rig in a power off state.  The relay k11 (click) is the only 
>> part that is able to operate in that failure mode
>> 
>> Chris
>> VE3CEA 
>> 
>> 
>> Sent from my iPhone
>> 
>>>> On Nov 8, 2022, at 16:31, gudguyham--- via Amps <amps@contesting.com> 
>>>> wrote:
>>> 
>>> It’s odd that it works on 120 and not 240.  I looked in the manual but the 
>>> terminal strip is not numbered on the schematic.
>>> 
>>> 
>>> Sent from the all new AOL app for iOS
>>> 
>>> 
>>>> On Tuesday, November 8, 2022, 3:24 PM, David Tenenbaum <dmt013@gmail.com> 
>>>> wrote:
>>> 
>>> Thanks for the feedback!
>>> I am still on the clock at work but took a break to check R8 and I am 
>>> seeing 3.98K ohms, so the 4k resistor seems intact. Later tonight when 
>>> finally done with work I will tear into it to look at the fuses and other 
>>> resistors, confirm there is REALLY 220 v getting to the unit, and anything 
>>> else that comes up.
>>> Thanks all for the ideas!!!!
>>> David N1RO/VE3TMK
>>> 
>>> 
>>>> On Nov 8, 2022, at 2:33 PM, gudguyham@aol.com wrote:
>>> Did you check R8 for open?
>>> 
>>> 
>>> Sent from the all new AOL app for iOS
>>> 
>>> 
>>>> On Tuesday, November 8, 2022, 2:20 PM, David Tenenbaum <dmt013@gmail.com> 
>>>> wrote:
>>> 
>>> Hi All,
>>> 
>>> I have an Alpha 86 that I have been using set up for 110v, and finally have 
>>> access to 220v, so looking forward to seeing what it can REALLY put out. 
>>> Unfortunately I have made the jumper changes (terminal in the back for 110 
>>> operation has locations 1&2 jumpered, 3&4 jumpered, and 5&6 jumpered, but 
>>> for 220 only locations 2&3 are jumpered), and the unit fails to light up or 
>>> come online. I hear a single relay activation when I hit the "On" switch, 
>>> but no lights or fan.
>>> 
>>> Fearing I hurt the unit I restored it to 110v operation and all is good. I 
>>> set it back to 220v and same problem. I checked continuity from the plug's 
>>> ground to chassis ground, and the hot leads show continuity to the right 
>>> places. I have been using a 220v SB200 on that outlet just fine.
>>> 
>>> Any thoughts or leads appreciated! Never thought I would have a problem 
>>> just switching supply voltages.....Scan of schematic attached....
>>> 
>>> Best,
>>> 
>>> David
>>> N1RO/VE3TMK 
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>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
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> 
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