View Full Version : IBM 5151-002 with On/Off switch? Original?

September 2nd, 2014, 05:56 AM
Hi Guys,

I've went to pick up both an IBM 5160 and 5170 yesterday and they came with an IBM 5151 screen, amongst some nice aftermarket cards... weird thing is though, that 5151 monitor has an On/Off switch. It kinda looks to be added afterwards, but I have to say it got me thinking if this is original or not (my guess is it would be added by someone, but still quite cleverly done then).

Here's some pics:

September 2nd, 2014, 06:34 AM
Not original, Looks a bit odd and out of place on a 5151 to me, Might look a bit better if it was a round switch.

September 2nd, 2014, 07:34 AM
It's a mod. IBM seemed to have originally intended end users to plug monitors into the female socket (IEC C13) on the back of power supplies (power-pass-through), and so the power-supply switch also controlled power to the monitor. Probably would've been less trouble to use a TSR such as BLANK-IT if s/he was worried about burn-in, however.

Personally, I like saving a socket, so I will actually buy NEMA 5-15R to IEC C14 adapters (http://www.jameco.com/1/1/52048-yl-3215-c14-nema-5-15r-plug-adapter-power-connector.html) for monitors which don't have a C14 connector.

September 2nd, 2014, 09:14 AM
When the C14 female adapters were still part of the standard setup for an AT-syle machine power supply, I was using surplus CAD monitors for large-screen displays with sync adapters. One of the first was a big Mitsubishi 20" monitor from a Daisy Systems rig with an EGA card.

It was heavy -- at least 70 lbs--and built like a tank. My desktop actually bowed under the weight. It also drank power, so I couldn't directly plug it into a standard PC for power. I took an inexpensive power strip and added a 115V 15A relay to it and used the PSU switched output to operate the relay. It worked well--and gave me the assurance that, unlike today, when the big red switch was "off", things were really "off", not just a simulation thereof.

I concur that the 5151 switch was added later. If one wanted to add one the "right" way, it might be better to replace the brightness pot with one with a switch attached to it--either rotate-to-dark or push to turn off types. No new holes in the case that way.

September 2nd, 2014, 10:39 AM
"An off switch? She'll get years for that!" :)