I still have a pulse line, so my old rotary dialer still works. Bell wants $3.25/month for tone service, I can do without 
I have all the Bell phone features too, just have to switch the phone to tone and away you go ...
I recall using some old Motorola CMOS parts to make some phones and ringers
MC145740, TP5089
I have all the Bell phone features too, just have to switch the phone to tone and away you go ...I recall using some old Motorola CMOS parts to make some phones and ringers
MC145740, TP5089
@Demian -- you might be amused watching this Youtube by "Marco Reps" on fixing up a Fluke 732A which went out of spec: Fluke 732A DC Voltage Standard & low cost DIY attempt - YouTube
The 732A is a pain to work inside the "oven". What I thought was a failure seemed to be a bad connection to a thermistor. Getting all the stuff back in with the foam insulator in place -not fun.
I'm really reluctant to change any parts that have not failed simply because it starts from an unknown state then. All the metrology stuff depends on long term predictability. The 732A seems to have the best track record, better than the newer 732B. Once you change something you open up the potential for problems. Still I would like to swap for a better battery/charger solution but it would need to be proven.
This reminds me that I need a fresh cal check on it soon.
Also on my bench now- The Optimation AC110 calibrator for calibration (a long story) 2 Fluke 932A AC meters, Boonton 9200A power meter HP 8116a function generator. Shortly- fix a funky oscillator in a Boonton 1120. No bench space left.
I'm really reluctant to change any parts that have not failed simply because it starts from an unknown state then. All the metrology stuff depends on long term predictability. The 732A seems to have the best track record, better than the newer 732B. Once you change something you open up the potential for problems. Still I would like to swap for a better battery/charger solution but it would need to be proven.
This reminds me that I need a fresh cal check on it soon.
Also on my bench now- The Optimation AC110 calibrator for calibration (a long story) 2 Fluke 932A AC meters, Boonton 9200A power meter HP 8116a function generator. Shortly- fix a funky oscillator in a Boonton 1120. No bench space left.
I worked aside the standards calibration lab, their Fluke 732A was playing up with the weekly measurement data. After some close observation of the following weeks with the assistant to the Electronic Meteorologist, if was found that the assistant regularly had fish and chips on Fridays at the company's local canteen. The oils on his fingers contaminated the banana jacks and the measurement leads that would cause electrical leakage. I don't think Sherlock would have solved the mystery, it was funny but a serious matter. The assistant was told to wash his hands after lunch, particularly on Fridays
Brilliant idea there Simon, the IC folder would be very compact and easy to find.
I worked on the VideoBridges as the product was being introduced to production at ESI and contributed several of the design’s changes as the product morphed into the final production system. Eventually, the original designers all left the company, and I inherited the whole design. I have a unit that was built from engineering parts I’d accumulated over the product’s lifetime and use it several times each month. I have a lot of old-timer stories related to my educational process of those years. If you have some non-functional VideoBridges, I may be able to help in your troubleshooting efforts. Please feel free to ask and I may be able to help. Remember . . . everybody is entitled to my opinion.
Can you forward this information to member 1Audio?
Thanks,
Carl
Can you forward this information to member 1Audio?
Thanks,
Carl
Hi Jack,
Demian's view on test equipment is bang-on. You don't want to replace any more than you have to unless it isn't critical and overheated. Power supply capacitors - sure. Many DIY attempts don't understand this.
Hi Carl,
I have a 2150 sitting here, I use it sometimes. I normally use an HP 4192A or little 4263A (bought new). I repaired a bunch of Videobridge 2150's for Partsxpress a few years ago. I think he tried with his own guys first.
I'll try to find Demian's email and forward your message.
Demian's view on test equipment is bang-on. You don't want to replace any more than you have to unless it isn't critical and overheated. Power supply capacitors - sure. Many DIY attempts don't understand this.
Hi Carl,
I have a 2150 sitting here, I use it sometimes. I normally use an HP 4192A or little 4263A (bought new). I repaired a bunch of Videobridge 2150's for Partsxpress a few years ago. I think he tried with his own guys first.
I'll try to find Demian's email and forward your message.
Carl:
I just saw your note. My Videobridges are all working OK. I only use one. Upgrades I would consider are repalcing the CRT module with an LCD or OLED display. Should be pretty straightforward I think if a suitable display module can be found. And replace the too noisy fan. I would have done that if it weren't so hard to get to.
The 2150 is still my preferred bridge for measuring passive components.
I just saw your note. My Videobridges are all working OK. I only use one. Upgrades I would consider are repalcing the CRT module with an LCD or OLED display. Should be pretty straightforward I think if a suitable display module can be found. And replace the too noisy fan. I would have done that if it weren't so hard to get to.
The 2150 is still my preferred bridge for measuring passive components.
Yes, the VideoBridge is heavy and noisy, and the video display has room for improvement, but mine sure gives good measurement results. My current quest is trying to figure out how to use the frequency and current selections to characterize the losses and hysteresis on some old pulse transformers to make some accurate SPICE models.
