dr bob

Dave,

I'd go that route if I needed to test this stuff more than a few times.

At least for my car, I tested once as a proof-of-concept exercise and then put everything back in the o'scope storage bin. Both DD's in the fleet have COP ignition, with no handy way to look at secondary voltage patterns. Plus with newer OBD systems, any aberations or failures trip a smart diagnostic alarm and the MIL. Diagnosing coil-and-distributor ignitions will very soon be an obsolete talent. Up there with carburetor refurb and tuning.

skpyle

Note, all further work done to the engine and accessories on the Red Witch will be documented in this thread:

https://rennlist.com/forums/928-foru...l#post14536481

90trunk

Seth,

I recently picked up a Sears Oscilloscope (which is the same model as your unit) on eBay. It came with leads, but no instruction manual. Would it be possible to purchase a copy of your manual? I have PayPal ready. I realize this is an old thread, but my online search for a user manual has been fruitless. Thanks for your consideration of my request.

Regards,

Craig

skpyle

Hello 90trunk,

I'll be glad to help you out. However, its going to be a bit. My scope is locked up in my storage building in the next town over. I will get to it when I can, and will scan the manual for you.

90trunk

Thank you so much! I appreciate your willingness to help me out.

skpyle

90trunk,

Hello! I have retrieved the manual from my storage bay. I have started the process of laboriously scanning the pages in as pdf's. Get a few more posts here on Rennlist so you can have access to private messages. Then, send me a PM with your e-mail address.

90trunk

Seth, Thank you for the update

90trunk

I’ve sent you a PM. 👍🏻

dr bob

Seth --

Please consider adding the manual scan to this thread as PDF, with the goal of enlightening some of us on the diagnostic capabilities of that o'scope. Using a generic o'scope for the duty is a little more involved due to different pick-ups and such, but perhaps the guide could be enhanced/adapted to let folks use such a generic tool on their 928's. The distributor functions like dwell and capacitor degradation don't apply to any 928, but we could add pickup signals from the early green-wire cars, knock and CPS sensor patterns, ignition final stages for EZx cars, etc. Make it into a 928-centric user-guide.

Follow-up with Dave -- Did you manage to scavenge the inductive timing light pickups you mention earlier in this thread? I have two, mismatched, and need to add BNC connectors to them so they plug into my very-vintage analog o'scopes. Should probably pull those scopes out and see if they still work; if they are like me, some critical component is probably leaking due to age and abuse. Hopefully they will still wake up!

skpyle

I will do just that once I've got the manual scanned in and saved as one pdf. Good point, as the manual is 60 pages and has pretty specific instructions and guidelines on the patterns expected to be seen.

ddire333

Would also love access to those expected wave forms if you can upload, I use my scope quite a bit on the 928, it can same alot of time but only if you have know good reference

skpyle

Sorry it is taking so long to get the manual scanned in. My familiarity with my scanner (or lack thereof) and my lousy scanning technique are causing delays. I have had to backtrack and rescan alot of the pages. Working 12.5hr night shifts isn't helping.

As a teaser of good faith, I am attaching the manual cover sheet and table of contents. I will have the rest of the manual scanned in and put together as one pdf as soon as I can.

ddire333

Thanks for taking the time to upload. While general scope use and sample "know good" wave forms are always useful, (picoscope website has some good info), having a set of 928 specific procedures and wave forms would be great. There are some if you look through the factory manual and Theo's very helpful diagnostic manual. Too busy right now but if I get time I would like to take on building on those. There is so much you can diagnose with a scope, amp clamp, inductive pick up, and pressure transducer - if you know what it should look like.

Here is link to short test I did last year re stalling issue I was having, through it could be fault with the ECU control of the icv, but the scope test ruled that out for me, turned out the coding plug had been forced in backward, no scope was going to help find that, have me chasing my tail for months.

90trunk

Thanks for the update, Threads like this show why the old school forums are a better tech resource than many of the popular social media platforms.

skpyle

I finally have all the pages of the scope manual scanned in as pdf's. As expected, it took longer than I intended because I had to refine my scanning technique and rescan pages. Often. I now have each page scanned as a clear, legible pdf with no blemishes or vague areas. They are being combined into one searchable document. When I get that document back, I will attach it to this thread.