bestie, I have no idea whether or not the particular circuit and ICs of the TT101 would be affected by lead length, but I am certain that some such circuits, using very wide bandwidth SS devices operating at high speed, are so affected. JP probably can answer your question specifically. |
It'd be great but you'd want to shoot yourself before you finished. There would be many pitfalls. Some of these circuits are affected by lead length, just to begin with. Also, it is a trick to get a multiple pin IC off a PCB and then successfully transplant it to a second PCB and have it work. Plus, you'd have to have the new PCBs made in advance, of course. It would be a heroic effort, either way. |
I'm too lazy to look at the video you quote, but the switch for "run" or "hold" makes no change to function quality. It only alters the read-out of the tachometer, in the ways that you have already discovered. I found the "run" display to be a bit crazy making, if you look at it for an extended period. I like "hold"; you can see what the tt is doing at a glance. |
Just relax and enjoy it, is my advice. I do believe that once these initial and endogenous issues have been dealt with by someone like JP, probably all will be well. But I have back-up tt's, just in case. |
Ummm.... Best-groove, what are you trying to prove? No one would contest the fact that the TT101 is temperamental. Least of all, me. So, I don't get it. Unless you're just trying to be funny, which is fine.
It's also a very fine sounding turntable when all is well. |
I think we all agree that the TT101 is fussy. That’s one way in which this hobby requires a relaxed approach. For my part, I can only thank JP for the excellent work he did on my unit.
Once JP educated me on the genesis of the issue with my TT101, I put a little space heater in my basement man cave, I set it to heat the room just enough to keep the temperature above 65 and control the humidity somewhat. I want say that I have had no problem since doing that, but wouldn't I be asking for trouble? |
It’s hardly a main stream item anyway, these days or even when it was current.
on the other hand, the TT101 and its ilk are now pushing 40 years old.
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I think JP would agree that the most likely story is that the crack was there since it left the factory or that the PCB swells and contracts with changes in humidity, thus rendering it susceptible to cracking at areas were expansion and contraction are constrained by the many fasteners that hold the boards in position. The latter hypothesis is consistent with my observation that it behaved differently (prior to repair) when it sat in our kitchen or a repair shop vs when it was set up in my basement audio system, where temperature is cool and air is moist.
My own TT101 came to me as part of a QL10 (TT101 chassis + plinth + UA7045 tonearm). The whole thing was "like new" when I bought it, possibly suggesting that it had had a problem from new. I purchased it very cheaply, described by the seller as "broken", on faith that I could fix it or find someone else to fix it. |
My own TT101 turned out to have a tiny crack in one of the PCBs which was finally diagnosed only after what had been an intermittent problem became a constant problem, enabling JP Jones of Fidelis Analog to sniff it out and repair it. But the defect in function of my TT101 was not like that reported here. Mine would come up to speed for a minute or two, then exhibit inaccurate speed for about 30 seconds, then crash. This problem came and went at first (the definition of "intermittent"), moving the turntable to various parts of my house would either cure or cause the problem, probably because moving the turntable was causing the PCB to flex where it was cracked, causing a short to come and go. JP tells me that he has since serviced other TT101s, and cracks in the PCB are not uncommon.
My TT101 and I have been happy together for about 2 years now. I use it regularly in rotation with 3 other turntables in two systems. |
Safesphere, You seem to be a fairly competent trouble-shooter, just based on what you've already done. When I first saw your post, I thought right away you must have a problem with the switch. I am told they are prone to malfunction mechanically. But if you're sure the main power switch is OK, you might look at any of the other switches on the panel. They may be wired such that any one of them can cause the failure mode you are experiencing. Think of it this way
at least your TT101 runs. Are there any other faults in its function? Because you seem to know how the switch is wired, I assume you already have downloaded the Service Manual, as Halcro correctly suggests. |
Unfortunately, the TT101 is very complex. Mine has nearly driven me nuts until I stopped fretting about it (because I realize that I also own 4 other great turntables that perform flawlessly, and it is of little consequence to me if my TT101 is a pain in the ass). Any of the hundreds of solder joints can have gone bad over the 30 or more years since they were built. Re-soldering suspect joints is a place to start. Another occult source of problems is those beige-colored multi-pin connectors. inside those connectors one may have a cracked wire or bad solder joint that is not accessible for inspection. I am about to ditch one of them and just directly solder the wires to the pins in hopes of curing a very elusive intermittent issue I have with mine. I was able to determine that tugging on the harness that goes to that connector can induce the failure mode I am trying to cure. |
Safesphere, Wish I could help, but you've already gone further than I in parsing out that circuit. Early on in the repair of my unit, I gave it to a very competent pro who found no issues with the ICs or the discrete transistors, after he replaced all the electrolytic capacitors. I own a 'scope but have never applied it to repairing the TT101, because the problem is very intermittent and elusive in the first place. |
Safesphere, I am bumping your thread. I did some re-wiring on my TT101 over the weekend, also found a bad electrolytic capacitor on one of the PCBs that are mounted under the top cover. (This was the only original lytic that we failed to replace on the first go-around, and it's the only lytic to be found under the top cover.) In the process of "improving" the wiring integrity, my other goal, I screwed up something. I need to ask you about the order of the wires in one of the connectors on that board. I hard-soldered them to the male prongs, because the connector was very loose. Now I fear I may have gotten the order incorrect. I will post the parts number for that connector, and maybe you can check yours for a reference. (The wiring is color-coded, as you know.) I turned what was once a rare intermittent problem into a consistent problem. Aaarrrggghhh!!! |
Safesphere and anyone else with a dismantled TT101,
The connector in question is nearest to IC810 on the Crystal PC Board Assembly, TDC-7B. This PCB is located under the top circular piece that surrounds the platter. TDC-7B is depicted on page 31 of the owner's manual. The order of the four wires going into this connector, as I have it, is: brown, (space), orange, yellow, green. Please check, if you can do it without much trouble.
Upon second look, I think I've got it correct, but I am grasping at straws, trying to figure out what I did that could have worsened my problem. I cannot find anything else that could be causing my TT101 to upchuck. Thanks. |
I did just that. Unfortunately I had unplugged this particular connector before taking a photo of that part of the PCB. Anyway, I hope Safesphere or some other TT101 owner responds, but if not, I do have the service manual which with some effort can be used to confirm the color codes of the wires. Actually, I am nearly certain I made no mistake, just grasping at straws here. Very weird. |
