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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