On Fri, Jan 2, 2026 at 6:59 PM Paul Koning <[email protected]> wrote: > > > > > On Jan 1, 2026, at 10:56 PM, Tony Duell via cctalk <[email protected]> > > wrote: > > > > On Thu, Jan 1, 2026 at 11:44 PM Nigel Williams via cctalk > > <[email protected]> wrote: > >> > >> Anyone know why DEC chose to use the grind-noise? it was a singularly > >> unpleasant sound, it had the effect of not wanting to trigger it. > > > > From what I remember it's actually a little relay on the main circuit > > board. A single pulse for the key click and a buzz for the 'bell' > > > > -tony > > That's what the schematic shows, or more precisely it shows a relay coil, I > can't find the actual part description.
I checked the printset after posting. The 'buzz' is generated by pulsing the coil from the firmware, it doesn't use the normally-closed relay contact to make a buzzer. > > Curiously enough, the earlier VT05 does have a proper beeper, with an 800 Hz > oscillator feeding a speaker. I looked in that printset too. A real speaker. Years ago I could have rescued a VT05. Alas the car was full (PDP11/44, PDP8/e, Acorn System 4, Northstar, Sun 3/260, manuals, etc) and I never went back for it. Been kicking myself ever since. > And the VT61/t, which is a block editing terminal for Typeset-11 in a VT52 > case, also has a speaker for the key click (and I assume for the bell/beep > though I didn't look that far). Then again, it's not clear whether the > VT61/t has anything in common with the VT52 other than its case and perhaps > the CRT and some of the power supplies. I remember a collection of rather > hairy looking circuit boards, the final last gasp of single-sided PCB > technology with hundreds of jumper wires on the component side... I think the VT52 is a pair of single-sided boards with lots and lots of wire jumpers. I've never actually seen inside one, I have a VT55 with AFAIK is a VT52 with the line/histogram board added. That is a double-sided (at least) PCB. -tony
