[Amps] AL-1500 fan speed switching

[Jim W7RY]

The later AL-1500 had a simple piece of plastic tubing glued to the 
chassis.

73
Jim W7RY

On 11/7/2013 4:58 PM, Alek Petkovic wrote:
> The AL-1500 does come with a chimney. It is glass. Yours may have been 
> broken by a previous owner and never replaced.
>
> I bought my AL-1500 second hand and the guy shipped it with the tube 
> installed. Needless to say, it was a mess inside, when I got it and 
> opened it up. The chimney was busted, as were the grid fingerstock 
> contacts. The pins of the 8877 were all bent inwards at about 30 degrees.
>
> I had an Eimac 8877 socket and chimney and so I used the fingers, 
> spacers and teflon chimney. I successfully straightened the tube pins 
> and the amp is running nicely to this day. I recently replaced the 
> marginally rated hv filter caps.
>
> Your tips for soundproofing and wire size upgrade are very good. I 
> will try that with mine. While I have it open, I will perform W1QJ's 
> hv safety mod as well.
>
> 73, Alek
> VK6APK
>
> On 8/11/2013 8:24 AM, Réjean Léveillé wrote:
>> Hi Ricks
>>
>> If you looked the amplifier rear panel, there is a spare hole located 
>> below
>> the main power K2 relay. I installed a small SPDT switch between 
>> medium and
>> high speed. To extend the two brown wires each side of SPDT with the 
>> center
>> for purple, see your instruction manual. I also added some sound 
>> proofing
>> under the top cover and against both walls where is located the blower
>> motor. Do Not put sound proofing material over the tube.
>> Now what I could not understand why there is no chimney, I fabricated 
>> one
>> with high temperature orange color silicon rubber sold at aircraft part
>> supplier. The silicon sheet glued with high temperature silicon glue. 
>> Also I
>> sealed all 4 tube box corners with high density tape. Now almost 100% 
>> air
>> flow must get through the tube, this keeps the RF section cooler and 
>> also it
>> cut down the fan noise vibration. The chimney end is about 1'' below the
>> cover. In fact I always keep the fan speed to high speed.
>>
>> I bought it second hand with Eimac tube, it got less than 10 hours. 
>> The guy
>> was too afraid to use it. I did full mods for HV section, 24v PS, vacuum
>> relays, inrush current filament, double all wires size for HV input 
>> transfo
>> and secondary 5v, chimney, added capacitors for 160m, operation LED,
>> soft-key circuit. Now it looks closer to top end and commercial grade
>> amplifier. At 1.5kw only 15-20ma Ig key down.
>>
>> 73, Rejean va2am
>>
>> -----Message d'origine-----
>> De : Amps [mailto:amps-bounces at contesting.com] De la part de rick 
>> darwicki
>> Envoyé : November 6, 2013 9:47 PM
>> À : AMPS
>> Objet : [Amps] AL-1500 fan speed switching
>>
>> Anyone have a clever way to add speed switching to an Ameritron, I.E 
>> have it
>> run on low in STBY and med or high in OPR ?
>>   I'm thinking at least automatically from the STBY/OPR switch for 
>> Low/Med
>> with an option to kick it to High for RTTY contests.
>>   Taking 30 screws out of the case is not a good option.
>>   A three position switch on the back panel is probably easiest but 
>> would
>> require getting up out of my chair hi hi
>> Thanks
>>
>>
>> Rick, N6PE
>> =======================================
>> The only difference between a rut and a grave is the depth.
>>
>> Website:  http://www.qsl.net/n6pe/index.html
>>   eBay Store:  http://stores.ebay.com/N6PE-Radio-Tubes
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>