[Bill Thomas]

     OK Folks, here we go!

     I've got a Technics SP-10 Mk II with a dead strobe light.  (Not an uncommon problem, apparently.)  The problem appears to be in the logic circuitry somewhere.  IC-7, IC-15 and IC-16 have been replaced.  (IC-8 and IC 12 have not - yet.)  The bulb has been checked and DOES work.  The Power Supply is putting out 134 Volts (unloaded).  When the turntable is plugged into the Power Supply, the Voltage drops to around 87 Volts, indicating a 10 mA drain on the supply.  This indicates that the driver transistors are on and pulling a load.  When the bases of the driver transistors are disconnected, the Power Supply goes back up to 134 Volts, so the transistors appear to be working properly.  Of course, there is no Voltage across the neon bulb, since the transistors seem to be fully "on", rather than pulsed.

     Anyone have any experience with this beast?  Any common "failure items", or is this just gonna be one of THOSE troubleshooting jobs?  (I'm afraid I know the answer to THAT one already!)

     Thanks for any help you might have.

Sincerely,

Bill Thomas

[macrojack]

Bill - I can't tell you where I saw this but it was a common tweak on these tables to disable the strobe because doing so  was supposed to help the sound. My strobe doesn't work and I never worried about it figuring that I can't adjust the speed anyway and maybe mine has benefited from the holy tweak.

Just leave well enough alone. How much do you want for it as is?

[Bill Thomas]

I remember that "tweak" from back "in the day."  But that isn't a satisfactory outcome.  The fact remains that there is something that isn't right in the unit.  In order to properly set it up, I need to KNOW all circuitry is in good condition.  You disable the strobe by pulling the fuse in the 140 Volt supply, not by melting down an IC.  It would be all too easy for a minor short to take down the rest of the unit in a MAJOR way.  I'm afraid I couldn't sell a unit in the condition it is in.  I would have ZERO faith in it.  By the same token, in totally working and properly adjusted condition, I'm sure you know what this table will sell for.  Perhaps you have a figure in mind?

     But, let's not talk about sales in a non-commercial area of the forum.  Feel free to e-mail me at nostubesforyourdynaco@gmail.com and we can discuss it further.

Sincerely,

Bill Thomas

[Bill Thomas]

     Just a note to let folks know the repair has been completed and the Strobe Light is now operating properly.  NOW, if someone wants to disable the Strobe Light, all they have to do is remove the fuse in the 140 Volt supply.  (That's the "normal" way to disable the strobe.)

     Leaving the strobe in a "non-working" state due to bad IC's would have been a VERY poor solution.  Defective IC's caused a great deal of electrical noise to be generated that *could* have affected other circuitry at any time, OR caused a failure that would require even MORE troubleshooting.  I simply could not accept that situation.  Once the strobe light was operating properly, it was easy to see that the turntable's drive motor circuitry was operating correctly with "rock-solid" speed regulation and control.

     There are a few more little "issues" to attend to, but I feel certain everything will be finalized before the weekend is over.  Whoever winds up with THIS turntable, they will have a properly operating unit with a completely rebuilt Power Supply and verification that ALL operational aspects of the turntable are functioning correctly.

     To the fraudulent eBay seller who ASSURED me that the Strobe light was "bright and beautiful", TTL IC's don't just "go bad" while sitting in storage.  You may have "gotten away with it" THIS time, but eventually, your lack of integrity will catch up with you.  I wonder what your Mother would say to you if she knew how dishonest you were?  You should be thoroughly ASHAMED of yourself.  Sadly, there is no shame among the truly greedy!

     However, the "laws of unintended consequences" still apply.  Because of this eBay seller's fraud, I wound up learning a HUGE amount of knowledge about the circuitry of a Technics SP-10 Mark II.  And in the immortal words of Emil Faber, (the fictitious founder of Faber College in "Animal House"), "Knowledge is GOOD!"

     Thus ends another chapter in the continuing saga of "Dishonest eBay Sellers."  Too bad there will probably be MANY more chapters to come!

     Sorry for the rant.  I'm just getting tired of the greed and fraud that seem to be permeating EVERY aspect of our society today.  As long as we are willing to allow it, we will ALL be poorer FOR it!

     Just MY nickel's worth!

Sincerely,

Bill Thomas

[Bill Thomas]

     I had *hoped* to have pictures today, but a mechanical "issue" has slowed down the process.  I *think* I'll have pictures tomorrow.

     The mechanical "issue" has to do with the mechanical brake solenoid assembly.  The previous "technicians" (at Harris Broadcast Service, no less) decided that rather than attempt to replace a couple of rubber bumpers and washers (that are no longer available, as far as *I* have been able to determine), they thought it might be a good idea to slather on a truckload of VERY heavy wheel-bearing grease; hoping that would act as enough of a "cushioning agent" to quiet down the solenoid.  Needless to say, it didn't.

     Instead, it caused the existing pieces of the rubber bumper and washer to turn extremely hard and then crumble.  Without the proper "cushions", the solenoid makes a VERY loud noise when it actuates, and when it releases.  The Harris boys then applied a "do not remove this sticker or warranty is void" label.  I suppose they didn't want anyone to see what they did.

     I am making a replacement rubber washer and will also *try* to fashion a replacement bumper for the end of the solenoid.  My first attempt at the bumper *worked*, but it isn't *quite* as "neat" as I would like.  My first attempt at fashioning a replacement rubber washer is also just *ok* at this point.  I have an idea that *might* make things a LOT neater and more "factory appearing", so I'm off to scrounge up the necessary supplies for the attempt.  I'll report back when I have achieved success.  (Or Failure, but let's think positively!)

Sincerely,

Bill

[Bill Thomas]

     Fabricating two little rubber parts took a LOT longer than originally anticipated, but they're FINALLY installed.  Now, the solenoid operates with a dull, *quiet* "tap", rather than a loud metallic "thunk".  Electrically and mechanically, this table is about as good as it can be.

     Here's the classic "Shot from Above" of the assembled turntable:

                   

     The turntable hasn't had a full cleaning yet - more like a light dust and wipe.  Overall, it just misses a solid Grade "A".  The biggest cosmetic "issue" has to do with the Start/Stop Switch.  Here's one picture:

                   

     And here's another picture from a lower angle:

                   

     Here's a shot of the Technics "logo plate" on the right front of the turntable.  It has some "issues" at the top of the plate:

                   

     Here's a picture of the platter with the Mat and the special screws removed:

                   

     And here's a picture of the Speed Change Switches and LED indicators.  Still a bit dirty.  It WILL look better after cleaning:

                   

     And finally, here's a "head-on" shot of the Power Unit:

         

     The rest of the turntable looks pretty nice.  It'll look even nicer after cleaning.  That's the next step, before we let this one find a new home.

Sincerely,

Bill Thomas