I fixed a United MIC4230, some sort of old, not so "hifi" gear. Found a shorted capacitor on speaker output (and really delicious smell of magic smoke). Replaced with a good Elna cap. Removed a piece of wrapped tape from the shaft of the pinch roller, in the the tape transport.
Then, relube of the worm drive in the cd trasport.
Radio receiver was strangely good.
Then, relube of the worm drive in the cd trasport.
Radio receiver was strangely good.
I got a bit bored, so I decided to work on a reel-to-reel.
It's an Acme 1500, (also sold under many other names) made in 1964, and no, it's not high fidelity, but it is cute.
Original price in 1964 was about $6.89, but I hear they're now going for $150 and up!
Needed all its capacitors replaced, a couple of PNP germanium transistors, and re-worked the dented drive tires.
Usual cleaning, adjusting, re-lubing.....also changed out the crystal mike element to a electret with some mods..... and guess what?
It works!
I recorded an opening clip from Mission Impossible on it for laughs.. "Good morning Mister Phelps.... this tape will self-destruct in 5 seconds!"
It's an Acme 1500, (also sold under many other names) made in 1964, and no, it's not high fidelity, but it is cute.
Original price in 1964 was about $6.89, but I hear they're now going for $150 and up!
Needed all its capacitors replaced, a couple of PNP germanium transistors, and re-worked the dented drive tires.
Usual cleaning, adjusting, re-lubing.....also changed out the crystal mike element to a electret with some mods..... and guess what?
It works!
I recorded an opening clip from Mission Impossible on it for laughs.. "Good morning Mister Phelps.... this tape will self-destruct in 5 seconds!"
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I always liked tape recorders. And one called Acme must be top of the range. 
But am recently concerned about the most serious threat to life on our Planet.
Covid-19? Carbon Dioxide? Radioactive waste? Man's inhumanity to Man?
NO. It's broken Office Chairs!
The Streets are infested with them.
Oh well. Guess it's another Engineering Fix required. This is what we do.
But am recently concerned about the most serious threat to life on our Planet.
Covid-19? Carbon Dioxide? Radioactive waste? Man's inhumanity to Man?
NO. It's broken Office Chairs!
The Streets are infested with them.
Oh well. Guess it's another Engineering Fix required. This is what we do.
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As some of you may know, I work on ships from time to time.
Some time ago, I met with the personnel from a company office who were in charge of buying, including office chairs.
They used to buy the top-of-the-range chairs.
All ways adjustable. Very comfortable.
With just one problem.
They all had wheels.
Not what you need an a ship that is rolling.
On receipt of a new chair, the wheels were removed or immobilised with gaffer tape.
All new chairs after the visit had no wheels.!!
.
Some time ago, I met with the personnel from a company office who were in charge of buying, including office chairs.
They used to buy the top-of-the-range chairs.
All ways adjustable. Very comfortable.
With just one problem.
They all had wheels.
Not what you need an a ship that is rolling.
On receipt of a new chair, the wheels were removed or immobilised with gaffer tape.
All new chairs after the visit had no wheels.!!
.
I made a change to my amp design to eliminate a strange situation where a LF impulse like a warped record would kick off an oscillation.
It turns out it was only partially stable, and connecting it to a free air speaker showed it. The speaker would move around centre position about 1mm either way like it was breathing at about 1/3Hz... My main speakers didn't show this so I never noticed.
So I've increased the gNFB resistor from 1k to 2k (this will work nicely with the reduction of gain I expect by adding a balance control), and adding a 0.033uF cap in front of the input making it a 2nd order filter instead of 1st order. Now, extremely LF spikes are fully suppressed, and a warped record won't put it into oscillation. Made the change to all the amps - result
For those who are interested, the filter is 0.033uF,1M,0.22uF,510k.
It turns out it was only partially stable, and connecting it to a free air speaker showed it. The speaker would move around centre position about 1mm either way like it was breathing at about 1/3Hz... My main speakers didn't show this so I never noticed.
So I've increased the gNFB resistor from 1k to 2k (this will work nicely with the reduction of gain I expect by adding a balance control), and adding a 0.033uF cap in front of the input making it a 2nd order filter instead of 1st order. Now, extremely LF spikes are fully suppressed, and a warped record won't put it into oscillation. Made the change to all the amps - result
For those who are interested, the filter is 0.033uF,1M,0.22uF,510k.
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Nothing too fancy today, just a couple of church organs. However one was a really nice-condition Hammond B3 with Leslie tone cab. Both were in pretty good condition for not having had any service in quite awhile - mostly just needed normal wear-and-tear stuff. It's nice to hear them sing so sweet once they're feeling better! I never grow tired of that sound.
Oddly, both clients paid me in cash, pretty rare these days! I feel like a drug dealer or something with this wad, heh. Off to the bank I go...
Oddly, both clients paid me in cash, pretty rare these days! I feel like a drug dealer or something with this wad, heh. Off to the bank I go...
Hee! This reads like the front flap of a Douglas Adams novel!
Key word being "infested," I hope not?
You, sir, are a braver man than I.
From the looks of the holes in that seat I'd say orifice chairs would be a better term!...NO. It's broken Office Chairs!
Working on a Seeburg "Library" jukebox for a buddy of mine. He had the mechanical aspects of it looked at a while ago, but when he used it, it would play one or two records successfully, and then he'd lose the sound, replaced by a crackling sound, and that was it. He could turn it off and later return to it, and the same sequence took place.
Yesterday, I shot the volume, bass and treble pots with Deoxit, and, as I had suspected, it works! I'm going to do a little bit more cleaning of tube pins, and I'll replace what tubes I can, but it's gratifying to quickly get something this nice up and running again.
Yesterday, I shot the volume, bass and treble pots with Deoxit, and, as I had suspected, it works! I'm going to do a little bit more cleaning of tube pins, and I'll replace what tubes I can, but it's gratifying to quickly get something this nice up and running again.
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Hopefully my wifes car. I say hopefully because we will need to see over time.
It had been intermittently coming up with a warning saying ESP fault visit workshop, usually accompanied by Brake Lights faulty visit workshop. On examination every time the brake lights were working fine. If you turned the car off and on the fault would clear. The last two times it went in for service it didn't do it.
Recently it started coming on more frequently and in the last couple of weeks it would come on before I reached the end of our st. So today I took out and cleaned all of the ABS sensors, and also removed the plugs and sprayed with contact cleaner.
I took it for a 6KM test drive and no fault, so fingers crossed.
Tony.
It had been intermittently coming up with a warning saying ESP fault visit workshop, usually accompanied by Brake Lights faulty visit workshop. On examination every time the brake lights were working fine. If you turned the car off and on the fault would clear. The last two times it went in for service it didn't do it.
Recently it started coming on more frequently and in the last couple of weeks it would come on before I reached the end of our st. So today I took out and cleaned all of the ABS sensors, and also removed the plugs and sprayed with contact cleaner.
I took it for a 6KM test drive and no fault, so fingers crossed.
Tony.
I used to work offshore on semi submersible drilling rigs.
Most of them had office chairs with wheels on them, but it was usually not a problem due to the gentle slow rolling of the rig.
Once we got hit by a bad storm and everyone in the office had to jam their arm rests under the desk to keep the chairs still.
This worked fine untill everyone in the room except for me went to lunch.
Suddenly I had 6 office chairs racing in my direction. I ended up sitting in the corner of my office surrounded by chairs.
A pair of Carver Silver 7t amplifiers. Standard Carver issues (which aren't bad by any means), and a solid performance upgrade. The customer will be completely gassed when he hears these again. Looking forward to his comments ...
Next on deck is a Carver M1.5 destined for the same treatment. The capacitor adapter boards available from Ebay and other vendors are garbage compared to the factory unit (I still have one - but it is sold). So, got busy and measured the factory PCB and designed (copied) that. The boards from China are perfect and accept the square mounting pins and snap type capacitors. Fits perfectly and has the angled edge to clear the chassis.
To those happy folks who use normal capacitors, with or without a PCB) - you're doing it wrong! To the cheap skates who don't even use a PCB, you are a hack, a complete hack! When I see these, they get a proper capacitor kit or I won't work on that item. Using normal leaded capacitors demonstrates a lack of understanding that shows you are not qualified to work on amplifiers. Especially not a Carver or any other quality amplifier.
-Chris
Next on deck is a Carver M1.5 destined for the same treatment. The capacitor adapter boards available from Ebay and other vendors are garbage compared to the factory unit (I still have one - but it is sold). So, got busy and measured the factory PCB and designed (copied) that. The boards from China are perfect and accept the square mounting pins and snap type capacitors. Fits perfectly and has the angled edge to clear the chassis.
To those happy folks who use normal capacitors, with or without a PCB) - you're doing it wrong! To the cheap skates who don't even use a PCB, you are a hack, a complete hack! When I see these, they get a proper capacitor kit or I won't work on that item. Using normal leaded capacitors demonstrates a lack of understanding that shows you are not qualified to work on amplifiers. Especially not a Carver or any other quality amplifier.
-Chris
Still working on it: Marantz "Gold series" PM150/ST150 Tuner/Amp from the early '80s. Sound out on one channel only unless you REALLY crank it up.
First, I'm going to replace the caps, see if that helps.If not...
Second, I'm going to "field strip" it and separate the metals for recycling. Marantz was crap in the '80s. Why did I even bother with this project anyways?
(Anybody here wants it? Yours for the cost of postage. Send me a PM or email.)
First, I'm going to replace the caps, see if that helps.If not...
Second, I'm going to "field strip" it and separate the metals for recycling. Marantz was crap in the '80s. Why did I even bother with this project anyways?
(Anybody here wants it? Yours for the cost of postage. Send me a PM or email.)
Hi Randy,
Depends on the circuit position firstly. Kemit is good, as are all other quality capacitor brands. Most people are not aware of this and search for the perfect capacitor. Buy axial caps to replace axial caps (not "orange drops" for gods sake!), and radial caps to replace radial caps.
Above all, the new capacitors MUST fit the board properly. If they don't fit, do not use them. Usually that means measuring the max diameter and length.
It is the dielectric of the capacitor that is important, not the brand. That and the build quality, so hand made capacitors are out! So are bees wax, oil and paper (PIO) types (garbage).
Hint, ESR doesn't matter at all! DA is the critical factor. Anyone who says different doesn't know what they are talking about. I have two expensive capacitor testers that measure all parameters (thousands each). I also have an analogue LCR bridge (GR 250DE), plus years of experience. Capacitors is an area where you have a lot of snake oil being sold by "experts" who test by ear only. Those folks are lost at best, total liars out for a buck often enough. Looking at the output spectrum of active circuits using different capacitors will tell you the truth about what is going on. I have for years.
-Chris
Depends on the circuit position firstly. Kemit is good, as are all other quality capacitor brands. Most people are not aware of this and search for the perfect capacitor. Buy axial caps to replace axial caps (not "orange drops" for gods sake!), and radial caps to replace radial caps.
Above all, the new capacitors MUST fit the board properly. If they don't fit, do not use them. Usually that means measuring the max diameter and length.
It is the dielectric of the capacitor that is important, not the brand. That and the build quality, so hand made capacitors are out! So are bees wax, oil and paper (PIO) types (garbage).
Hint, ESR doesn't matter at all! DA is the critical factor. Anyone who says different doesn't know what they are talking about. I have two expensive capacitor testers that measure all parameters (thousands each). I also have an analogue LCR bridge (GR 250DE), plus years of experience. Capacitors is an area where you have a lot of snake oil being sold by "experts" who test by ear only. Those folks are lost at best, total liars out for a buck often enough. Looking at the output spectrum of active circuits using different capacitors will tell you the truth about what is going on. I have for years.
-Chris
Chris is right.
Caps are one of the biggest snake oil ventures these days.
All the marketing and hype in the world isn't going to nut my brain with illusional descriptions.
I've been using simple and inexpensive Xicon caps in most repairs.
Never ever had an issue, the customer is pleased, and that's fine with me.
Caps are one of the biggest snake oil ventures these days.
All the marketing and hype in the world isn't going to nut my brain with illusional descriptions.
I've been using simple and inexpensive Xicon caps in most repairs.
Never ever had an issue, the customer is pleased, and that's fine with me.
Attachments
just made worlds first Blue Yeti mini usb Microphone conversion to USB-C. worlds-1st-usbc-Blue-Yeti — ImgBB
OG-Blue-Yeti-mini-usb — ImgBB
OG-Blue-Yeti-mini-usb — ImgBB