[Amps] TL922 Filament Transformer (Was TL922 Fan)

[Jim]

Here is the corrected schematic.

Thanks
73
Jim W7RY

On 5/9/2019 6:58 PM, Jim wrote:
> This diagram shown below is *WRONG. DONT USE IT!* Its the exact same 
> as a TL922.
>
> I'll get the proper circuit drawn and send it out.
>
>
> Thanks
> 73
> Jim W7RY
> On 5/8/2019 7:54 PM, Jim wrote:
>> Because you say you want to ground the grids and do other updates.
>> *This is what you said:*
>>
>> /*_Tomorrow I will detail the rest of the TL-922A makeover, new tube 
>> sockets, new band switch, new tubes and a W8JI grid grounding party_*
>>
>> /Which means to me, that you are going to do other work? So what does 
>> this mean to you?
>>
>>
>> What I said is exactly what I mean. If a tube shorts, (filament to 
>> grid which is the only way I have seen a 3-500 tube short, and they 
>> do it often), it shorts the 120 volt DC bias and relay supply to 
>> ground, and burns up the filament transformer, because it has no fuse 
>> (fuse wont protest it anyway, putting a fuse in the primary does not 
>> keep it from burning up). Every wonder why so many TL-922 filament 
>> transformers go bad? This is why they do.
>>
>> Only fix is to re-wire the relay bias switching.
>>
>>
>> *Bottom line...*
>> if you wire it like this, (from an SB220 schemaic) it will save your 
>> filament transformer.
>>
>>
>> Thanks
>> 73
>> Jim W7RY
>> On 5/8/2019 1:28 PM, Artek Manuals wrote:
>>> Jim
>>>
>>> A perhaps important point but I am not sure what it has to do with 
>>> the fan replacement?
>>>
>>> Maybe you would just like to point us at a solution to the mentioned 
>>> problem rather than have us reinvent the wheel
>>>
>>> ?????????????????????
>>>
>>> Dave
>>> NR1DX
>>>
>>> On 5/5/2019 9:29 PM, Jim wrote:
>>>> You have not mentioned the most important part...
>>>>
>>>> Re-wiring the 120 volt cut off bias.� If a tube shorts, it takes 
>>>> out the filament transformer.
>>>>
>>>> Study the schematic.
>>>>
>>>> Thanks
>>>> 73
>>>> Jim W7RY
>>>>
>>>> On 4/29/2019 7:52 PM, Artek Manuals wrote:
>>>>> OK after a bit of sleuthing and help from the A/C repair guy next 
>>>>> door who has a meter that measured the airflow I found two 
>>>>> probable exact replacements for the fan in the TL-922A... Which 
>>>>> suggested that this was an ~53CFM fan that originally was spec'd 
>>>>> at 100V/7W probably 1700RPM. Size: 120mm x 120mm x 38mm
>>>>>
>>>>> The first from Mouser is a Sanyo Denki fan #109S006 a very quiet 
>>>>> fan at 28dBa. Problem is that it is a non stocked item with a 
>>>>> minimum order quantity 40pcs at $24.76 ( extended order price of 
>>>>> $990 !) ... deal breaker for sure
>>>>>
>>>>> With the spec sheet for the Sanyo in hand I could now look for 
>>>>> other equivalents ! . I found the following on Amazon.
>>>>> "AC Infinity LS1238",� 62 CFM @32dba� 120V/8W (probably 7W at 
>>>>> 100V). $14.99 free overnight delivery ...Bingo
>>>>>
>>>>> Easy replacement. The new fan though rated at 62CFM measured 
>>>>> closer to 55CFM installed in the amp. The old fan would raise the 
>>>>> noise level at the operating position when switched on by 
>>>>> approximately 12dba as measured with two different phone apps. The 
>>>>> new fan switched on raised the noise level by only 2db when 
>>>>> switched on a big improvement over the old worn out one. Air exit 
>>>>> temperature was identical to the old fan at around 30C at idle and 
>>>>> 35C key down for 2 minutes.
>>>>>
>>>>> So TL-922 owners� print this info out and store it with your manual
>>>>>
>>>>> Tomorrow I will detail the rest of the TL-922A makeover, new tube 
>>>>> sockets, new band switch, new tubes and a W8JI grid grounding party
>>>>>
>>>>>
>>>>> Cheers
>>>>> Dave
>>>>> NR1DX
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
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>>>>
>>>
>>
>