Re: Unusual TM5xx(x) MF - its not a TM500 or a TM5000


Hi Hawker,
How do you know the TM504A was designed for audio work??? This is the first I heard of this special adaptation. Is this an option listed in the catalogs? Does it say that in the service manual somewhere?I also have a newer TM500 MF. Mine is a 6 slot MF. It looks exactly like a TM5006 on the front due to the color scheme and the plenum below the MF. It says TM506A in exactly the same place the TM5006 label would be. I thought I was buying a TM5006 until I got it home and noticed there were no GPIB connectors. Even now with the TM506A in a stack of three TM5006s I can't tell which one is the TM506A unless I look carefully at the label on the front.
The TM500 and TM5000 MF fans are a source of numerous noise complaints. About 1/4 of my TM mainframes have fans that cause me to grit my teeth when I turn them on. But when I think about the hassle of replacing them I quickly chose to accept the noise because if I was going to replace one of then I would probably choose to replace them all. I have 15 TM506 or TM5006 so that would be way too much work.
Dennis Tillman W7PF

-----Original Message-----
From: Hawker
Sent: Tuesday, April 09, 2019 10:21 AM
Subject: Re: [TekScopes] Unusual TM5xx(x) MF - its not a TM500 or a

I wonder if that is different than the A series?
I have a TM504A. AFAIK the 504A is a 504 beefed up (bigger caps and
pass transistors) and fan specifically designed for the audio
distortion analyzer and signal generator plug ins. It has a fan but
does not have the lower venting.of the TM5000x series. It also does
not have GPIB as the OP mentioned. It is not a 5000x series but a 500
series main frame. It does look more modern than a TM504 but not as
modern as a 5000 series or as tall.

The funny thing about the TM504A is, although it was designed for
Audio plug ins, the fan is so crazy noisy I can't stand to use it. I
did replace it with a lower noise fan, with the same air flow, but it
is still really noisy and I can't stand to use it unless I have to due
to this.

Dennis Tillman W7PF
TekScopes Moderator

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