This one seems to follow in the outlook as the internals look great and lightly used.
The strobe tunes seem to have a much better life and only turned on when needed and even though they are old from the '70s and have external damage they have very low hours of use compared to other musical gear. I was also thinking that this type of gear is not like amplifiers that are used hard cranked up and left on for thousands of hours during their life. removed from PCB Tested then reinstalled back to PCB. All capacitors and transistors that were tested, were desoldered, i.e. At this point, they all appear to be good so I have not done an ESR test on the caps. I do have an ESR tester, However, without any leaking swelling or signs that any caps are bad I did not see the need to test the ESR I would have to look up each cap datasheet and find the proper test frequency. There is also a transistor (Q1) I pulled and it tested (good) as well. All capacitors on this PCB tested (good). two 2000nF 50V electrolytic caps and one 20nF 350V cap. on this board, there were one more of the 150nF 25V Illinois caps.
Next, I pulled the power supply PCB with the goal of testing all the electrolytic capacitors. However, everything seems to be good on this board other than the one cap I replaced. I happen to have a few 150nf 25V TTA Illinois caps in my parts bin. it was detached from the body of the capacitor. on this board there are two 150nF 25V Illinois Axial caps one of the two caps had a lead broken off. The motor does spin freely by hand and the bearing feels good. I am not familiar with these motors but I think the black wire is connected inside the motor. I believe this means the motor is testing as (good) and is not shorted and in working condition. I ohm tested the motor wires test (R) & (W) to (B) test at 32Ω, (R) & (W) to frame test OL or open circuit. the motor has two black leads and one red and one white lead. Next, I disconnected the Hurst synchronous motor. I don't see any sign of leaking or swelling of the caps. I believe this is correct and means the cap is testing as (good).
Peterson strobe tuner vintage series#
Testing in parallel as 10uF each leg and series as 5uf. I tested the electrolytic Caps the 3uF & the Dual 10uF Capacitor (good), The dual Cap is one I have never seen before, it's an axial dual cap with one negative leg on the one side and two positive legs on the other. Then I pulled all 4 transistors on the board the (Q1) MJE711 the (Q2) MJE721 the (Q3) 2N3414 and the (Q4) 2N3405 all 4 tested good. I probably should have started on the transformer rails but I did not. My first instinct was to go straight to the motor drive PCB. I did find one thread on the model 400 with a similar issue however it is not the same unit and did not help me with my issue. This is when I decided to reach out to a friend and get the schematics for the unit and then started to troubleshoot. when I powered on the unit, the motor would jump moving about. Hurst synchronistic motor was not spinning. Unfortunately, My first gut instincts proved to be correct yet again. It was a while before I started to feel good enough to take a look at my new strobe tuner, the 17th was the first day I felt like taking a look at it. I ended up in the hospital and diagnosed with pneumonia. A few days later I had a fever of 104.6 on Dec 3rd. It just so happened that on Nov 30th she was tested positive for Covid.
My wife works on the front lines of the Covid epidemic. I was now the proud new owner of a Peterson strobe tuner model 420. I made an offer to the seller, The offer was excepted. I decided to purchase it only if I could get it at a price that would make it okay if the unit needed repair. I ask the seller he stated it seemed to be spinning and working fine. I was not sure if that was from the frame rate of the camera or if it was not spinning. However, I noticed the strobe disc appeared to be stationary. I thought there could be an issue, the photo's listed for the unit did show it powered up. The seller did not have the ability to test the unit. Finding one for a fair price is rare, most people think they are made of gold or something. I found a Peterson model 420 for sale and listed for a fair price on Nov 26th. but I think that is how most amateurs feel in any hobby or field they are still new too! I have played guitar off and on for many years. I always feel ignorant when I take on a repair. especially when it comes to understanding schematics and following signal paths. I am still far down the Amateur ladder and have a lot to learn. However, I am just an Amateur who is enjoying the path of learning electronics and repair for my personal benefit and enjoyment. I do have a nice Amateur lab with brand name Osiloscopes, power supply's, bench meters 6.5 digits, Electronic load, cheap signal generators, and some other decent gear.
Peterson strobe tuner vintage professional#
Hello again, to everyone on the EEvblog! I would like to start out by making it clear I am not a professional in electronics repair.
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