Re: jobs from hell

Don Black <donald_black@...>

I wonder if reducing the lamp voltage slightly to increase their life would be worthwhile? Perhaps a silicon diode in series with their supply would give about 0.7 volts drop and improve life (a diode would give a constant drop however many lamps were lit where a resistor would depend on load).

Don Black.

On 17-Jul-13 3:38 PM, David wrote:

On Tue, 16 Jul 2013 17:50:00 -0600, David DiGiacomo
<daviddigiacomo@...> wrote:

>> Was it the pushbutton switches which they kept in later plug-ins or
>> the relays? I imagine those relays were expensive which would be
>> another reason to get rid of them.
>I'm not sure what you are saying, but the white relays were used in
>the 7A13 for a long time after the 7A12 was gone.

The 7A13 "pull for x10 Vc" function would require another x10 switched
input attenuator to implement without relays.

I am just suggesting that Tektronix made more effort to stop using the
relays than to stop using the pushbuttons. I remember seeing a price
list somewhere showing that Tektronix was OEMing the relays for a
price in the $50 range until alternative products became available.
After a certain time, it seems like the 7A13 was the only product
using them.

>Also, there are lots of other plugins (and mainframes) where changing
>the lamps is no fun at all. Soldering incandescent lamps just seems
>like a bad idea.

I think the only problem is easy access which as has been pointed out,
is a major problem in many cases. My 7A12 needs new bulbs installed.

The on flakey pushbutton switch that I need to repair is on my 7T11A.

Join to automatically receive all group messages.