For Giggles what watchmakers used in the 1980s!! - Page 1
Forum section: electronics / general

author: watchmaker
author_rank: Unknown
timestamp: January 20, 2024, 07:22:52 pm
content: This is an MU-700 that I still prefer! It was a service center level instrument in the late 1970s and throughout the 1990s.It is used to time Accutrons and Quartz (timing only) while it provides diagnostic data for case mechanical watches (error rate, amplitude of balance oscillation and error in impulse delivery (Beat error).Look at all the ICs it required. The ball chain driven scale is the primary failure point while the power supply is second.Only the most successful watchmakers could afford this, and it shows how scared everyone was of quartz at the time. Had to be "with it".

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: January 20, 2024, 10:47:10 pm
content: Fascinating. I can't however picture in my mind how this is used. How is a time piece connected.?I understand how you can get a beat frequency compared to a reference oscillator with an oscilloscope so this device must have competed with cheaper CRO's of the same vintage.

author: factory
author_rank: Super Contributor
timestamp: January 20, 2024, 11:49:03 pm
content: Quote from: watchmaker on January 20, 2024, 07:22:52 pmThose blue tantscan't be far behind in the list of failure points along with the IDC connectors.David

author: jchw4
author_rank: Regular Contributor
timestamp: January 21, 2024, 08:33:54 am
content: $2,619.00 1980 US dollars? How much is it in modern USD? $26k?

author: ebastler
author_rank: Super Contributor
timestamp: January 21, 2024, 09:11:31 pm
content: Engineered and made in Switzerland, of course!Portescap is still around, by the way. They have divested their watch-related technologies decades ago and are known as a maker of micromotors today.

author: schmitt trigger
author_rank: Super Contributor
timestamp: January 21, 2024, 09:23:00 pm
content: There is this thread, where the OP asks what would be the usefulness of NOS stock of 74xx TTL chips.https://www.eevblog.com/forum/beginners/new-olds-stock-(nos)-74-ics-(advantages-disadvantages)/?topicseenWell, if you require to repair one of these instruments, it would definitely be helpful.

author: Veteran68
author_rank: Frequent Contributor
timestamp: January 21, 2024, 10:49:17 pm
content: Quote from: jchw4 on January 21, 2024, 08:33:54 am~$9700. About 3.72x inflation rate between 1980 and 2024.

author: watchmaker
author_rank: Unknown
timestamp: January 22, 2024, 10:34:43 pm
content: Quote from: jchw4 on January 21, 2024, 08:33:54 amI was waiting for someone to notice the invoice. In 1983 I was a newly minted Ph.D.working for a USAID program for $40K and I was not unhappy. A watchmaker paid good money for this and these were still used in the USOmega Service Center until the mid 1990s.Quote from: chickenHeadKnob on January 20, 2024, 10:47:10 pmThe way this works:Two microphones, one inductive (which I ignore and is only used for timing quartz qnd tuning forks) and the other is aoustic for mechanical.The lever on the right selects the function and LED scale. This reports daily rate error soen to the -2+2 range. In 1980; when quartz mass produced quartz could not keep time (think PC clock errors). So a lot went into this time reference.The lever selects the function and LIFTS the scales via a chain drive to the correct position.Error rates and beat error are relatively easy. Just picks up the sound when the escape wheel tooth locks on one of the two pallet stones.An interesting factoid is that the balance does not have equal excursions on both halves of the oscillation. This was empirically demonstrated to us (but I forget how). And a beat error of less than .1ms does not have a significant impact; but over 5ms it can be dramatic. This has to do with delivering impulse (and it really is impulse) when the balance impulse is before or after it's center line with the pallet fork (which delivers the impulse).Amplitude is the tricky part. It involves knowing the portion of the balance rotation that the balance jewel is in contact with the pallet fork. This is called lift angle and the purpose of the thumbwheel on the upper left is to imput the lift angle so the amplitude can be calculated. The signals are the sound of the pallet for hitting the impulse jewel on the balacne, and the sound of the escape wheel locking on the pallet jewel.It may help to look and oscillograph of a watch tick. There are five distinct sounds.It took some figuring to design a system that could precisely and repeatedly measure the intervals of these sounds.Today, such instruments are a tenth of this size and there are even smart phone apps. But forty years ago this is what was required to produce accurate and reliable results.Oh, and these automatically selected the correct beat count (Beats per hour). These range from the most frequently used (18,000 BPH/5Hz) to 36000 BPH; the higher beat counts being less influenced by external shocks because of the time intervals.I much prefer this particular instrument to the Chinese instruments ($100), ar the newer Witcschi instruments ($3k USD and now required to hold an account). I have a couple as a back up although it is easy to repair the power supply. The only chip problems I had were chip creep. I think they gave a lot os space to vent heat.

author: tooki
author_rank: Super Contributor
timestamp: February 10, 2024, 12:21:50 pm
content: Quote from: watchmaker on January 22, 2024, 10:34:43 pmI really appreciate that the vendor made sure to specify that the year is “AD 19___”. Wouldn’t want someone thinking their payment was due in 1980 BC! 🤣