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jeffs

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About jeffs

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    TO-18 Transistor

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  1. looks great! ..... but far too neat and much too much sun light for a shop....LOL.
  2. I've noticed this as well and it's puzzling how these things could be so consistently beat up. My guess is that their weight/size ratio is large. Someone picks up a unit but miscalculates the weight based on relatively small size ... immediate drop.
  3. I've found it very difficult to sell anything on this site. Everyone wants a deal or wants a unit they can mod themselves (myself included). I stopped trying. I just go right to ebay and take the hit. I sold 6 amps in the last few months, only one of them on this site. I used to think this would be a good place to sell, but with m1.0t mkII barely moving at $550 .....
  4. If still time .... In with 83
  5. The transformer is inconsistent from unit to unit so you're right, it's difficult to make changes that will work the same across all units. I've added regulators to several BillD C-1. To test regulation, I also added additional load without issue (about 50mA), but admittedly, not for any significant duration. I've also had a C-1 that had such a weak transformer that I'm not sure there was enough output for a 12V LDO to even operate properly? The stock opamps combined maximum operating current is about 100mA, maximum, 45mA typical. (+/-15V supplies) Replacing all opamps with OPAx134 would increase this to a maximum of 180mA, 144mA typical. I believe that anyone who wants to do mods to a C-1 should first look at the voltage levels at the PS rectifiers. If they are <14V, the transformer in that unit is crap. For that matter, one can just look at the factory values of R404 and R405, if they are less than 20ohm, the transformer in that unit is crap. This is not to say that higher levels mean the transformer is great, but the weak transformers are certainly a problem.
  6. No ..... but ...... I needed a few parts from Mouser, and I have one more C-1 at home that I want to do at some point, so I just added the regulators and heat sinks to my order. Arrives next Monday. I have posted a few pics in the past, but when I get the parts, I plan to write it up with pics. Probably get to it some night next week. It's easiest to do it while doing the BillD mod, but can be added at anytime.
  7. The power supply in the C-1 is a poor design. The 12V supplies are unregulated. I don't understand why people go to the effort of doing the BIllD and don't address the +/-12V supply, or even worse, they address it by just lowering the values of R404 and R405. In one case I read a post where the modder purchased an entire range of 1/2W resistors in order to trim the 12V just right. Too much effort. If you use headphones, which introduce the most significant load change, things go out of whack again. Replace R404 and R405 with LDO regulators. Cost = $5-6 including heat sinks, added effort is minimal.
  8. Man ... I thought I had strong dose of the disorder. LOL. All looks great!
  9. I half-heartedly bid on this one. Was tempted to break my personal bidding rules - but didn't .... set my max and didn't rebid. If it was non-inverting I would maybe go higher. I just fixed an amp that Ive had for a while, some assistance from @dennismiller55. I do remember paying more for it than the $178, and it did have a tricky problem, so I guess there are still some reasonable deals. Not much inventory and rarely anything locally of any reasonable cost.
  10. Prices are noticeably higher since a few weeks ago! I look mostly at m1.0t, m1.5t and m500(t). A recapped inverting m1.0t just sold on ebay in about 10 minutes, $400. Going back a few months, nothing higher than $300 or so. A good unit went for $237 within the last month. No inventory. Prices on repair units are in the $200 range - maybe even higher for m500t. I have a bunch of extra amps but I'm going to hoard for a while 😊 ....
  11. I thought your m500t was well priced considering the physical condition and also the fact that you had replaced all of the most likely failure candidates. It's good to see that the ebay community recognizes the value in this service. There was a time when it was difficult to get any extra $ based on a recap. I've noticed that changing lately.
  12. I never gave this much thought, but recently have realized that the younger generation is challenged when it comes to the meaning of this day. My Mom is recently in assisted living and I realized it would be the first year since my Dads passing that she would not be able to visit the gravesite. After visiting her with my youngest daughter, we went to the cemetery and tidied up the area. One of the local volunteer groups had put flags in place for those who served and it was nice to see one at my Dad's stone, though he did not die in service. The best part was my daughter took pics of the main family stone with names going back 3 generations and during the 45 min car ride home, she asked lots of questions about family history and the roles of those who served in the military, including one member who died at Iwo Jima. Educational for both of us.
  13. jeffs

    Chernobyl

    Yup - me too. Clever ploy by HBO ..... start a really good series a few weeks before GOT is over for the season (or over for good). Keeps people subscribed that might otherwise cancel ..... at least for a little while longer.
  14. Happy Birthday JohnRotten!
  15. recapping is a big part of the BillD mod. Best to buy a functional unit , then get the BillD done. they have been pretty scarce for a few months.
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