clock with Sperry SP-151

[N9KTW]

Hi All:

With the "shelter in place" going on I have a lot of time to work on the projects that have been "staring at me"

I have a Sperry  "evaluation" clock which uses the sp-151 + sp-232 displays.  I acquired it in 2015, and it has never lit up as long as I have had it. I went and replaced capacitors, transistors, and resistors (I think on the resistors), with no luck. I have also tried swapping the MM5314 chip with a working pull.  Still nothing. 

Is it possible that the displays have merely reached the end of their useful life and are just no good?  I have the manuals for the clock and am at a loss as to where to go from here. Can anyone help me ? I would love to get it working, as there is a special place in my heart for old electronics (my XYL, and Accountant both HATE my Heathkit GC-1195 With the chime kit that I restored the case and converted the display to LED's) 

Anyone have any ideas where I should start looking for problems?

de Howard, N9KTW

[Dekatron42]

Have you checked the voltages from the power supply?

Have you checked that the voltages reach the IC, transistors and displays?

Do you have a plasma ball that you can hold close to the displays to see if they glow orange?

/Martin

[alb.001 alb.001]

if you can remove the displays from the board, I would try holding a small high voltage high frequency AC source near them and see if the neon turns on  - you do not need to touch the pins to this high voltage  ( I use my trusty  DermaWand  )

hope this help

Phrama Phil

--
You received this message because you are subscribed to the Google Groups "neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+...@googlegroups.com.
To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/c8d0b520-e260-459c-a5b0-b61934821e08%40googlegroups.com.

 

[jf...@my-deja.com]

I had one of these evaluation kits, and I recall that the displays were socketed.  If you have an oscilloscope, you should do some basic debugging.  I would start at the power supply (one of my nixie clocks used a Signal Transformer of the same vintage that died due to an open primary).  If you have all the proper dc voltages, I would next check the logic level signals: the 60 Hz reference and the MUXed segment and digit drives.  Finally, check for proper waveforms at the anodes and cathodes.  Since nothing lights, I would suspect a bad power supply or a construction error like swapping the pnp and npn transistors or backwards diodes.

I have mentioned this before, but the MM5314 does not have very good noise rejection on the clock reference input, so power line spikes tend to make it run fast.

[gregebert]

The SP-151 is durable; I built a wristwatch a few years ago with the same unit my father got as a sample back in 1974. In fact, the prototype on my workbench is still running after 5 years on the *same* charge I put on the Li-ion battery (yeah, the battery drives the display and the RTC).

Somewhere in my archives is a set of schematics for using Sperry displays as clocks; let me know if you need them. I recall the circuit requires some switching to get the segments to light, so a scope will be necessary for debugging.

[jf...@my-deja.com]

Also, as I think about it, there is a "keep alive" element, and you should make sure it is energized at all times.

[jf...@my-deja.com]

I agree.  I forgot that one of the first things you should do is apply HV (like 150-200V) directly to the tubes,with a series dropping resistor of 47K-220K, and make sure it glows under these conditions.  I realize that this assumes you have access to an electronics lab...

On Saturday, April 25, 2020 at 10:48:28 AM UTC-7, gregebert wrote:

The SP-151 is durable;

[N9KTW]

Here is the latest:

The suggestion of a high frequency source was super.......I got out my "semi-obsolete" gas lamp tester, and established that the display is no good. found a second complete display board in the box of parts, and tested it , it isnt completely good either, but good enough for testing..... some segments arent any good . , and the seconds portion is totally out. 

I guess unless I can find another display this isnt happening as originally designed :( . Also the minute display seems to be running like a seconds display (problem for another day)

Really dumb question...... anyone have or know of a source for a new display????

Thank you guys for the help thus far.... I am sort of making progress....

de Howard, N9KTW

[N9KTW]

Well I have good news! 

I got it going (aside from the non working seconds display) ....

the final solutions were as follows:

  1) replaced 2 bad driver transistors for the display (I had bought a bunch when I first started restoring this)

  2) replaced the MM5314 chip.... this was the problem with not being able to get the clock to keep time (found a spare in another pile of clock parts....

Thank you to everyone for the help and pointers of where to look. 

I am posting pictures of the clock in operation , eventually I want to male a clear acrylic box to house it . 

de Howard, N9KTW

 

[Nicholas Stock]

Is your SP332 dead? I have one in the man cave that appears to be NOS and still has gas. It's yours for the price of postage..

Cheers,

Nick

--

You received this message because you are subscribed to the Google Groups "neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+...@googlegroups.com.

To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/b77a4c82-6552-47aa-8e8a-71c74326bbe0%40googlegroups.com.

[N9KTW]

Nick:

yes unfortunately the 232 is dead . I go no illumination with the tester on either of the 2 i have (1 was on the original board, and the other on the "new" board).

Please let me know what the shipping would be, and the best place to contact you so we dont share too much personal info on the board. 

Talk soon. 

de Howard, N9KTW

[Nicholas Stock]

PM me at nick...@gmail.com

Sent from my iPhone

On Apr 26, 2020, at 07:31, N9KTW <n9kt...@gmail.com> wrote:



--

You received this message because you are subscribed to the Google Groups "neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+...@googlegroups.com.

To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/ea1cd79f-2f95-431a-9777-3ce18041d6d8%40googlegroups.com.