What goes bad in record players with Pickering V-15 carts?

[1922VV111]

Ok. This is a specific issue that has me baffled. Over the years I’ve picked up some higher end portable turntables they have Pickering V-15 carts in them and Garrard changers. but it seems the pre-amps are bad in all of these if I use the built in amps there is no audio output. But If I plug the turntable outputs to a separate amp they play just fine and sound quite nice, but it defeats the purpose of being “portable”. What fails in the built in amps of these portables?

[TC Chris]

Wow, could be anything. But if it's both channels in a stereo device, look for things common to both channels, like the power supply. Power transformer bad? Rectifier? In early diagnosis, the voltmeter is your friend.

Chris Campbell

[electra225]

What Chris said. You also need a schematic...

[1922VV111]

What Chris said. You also need a schematic...

These are also early solid state phonos (like a Sylvania Exponent 4/40)...I guess a transistor goes bad? I'll be honest I'm a lil intimidated when I see schematic. I need to watch some YouTube videos on how to actually read them! This is how little I sadly know. Like I said I'm more knowledgeable about acoustic spring driven phonos than I am with electronics.

[TC Chris]

When I was a kid, dealing with tube stuff, I always assumed that the problem was a tube. Often not that.... Always look for the simplest explanation or the most common device, like bad switch contacts or capacitors that have gone south.

I recently diagnosed and repaired a Heath receiver with one channel out. I had great help online from a very knowledgeable guy across the country who had written an article about a similar device. I actually found the problem early on, a bad resistor, a 5-cent part. But I replaced it with a mistaken one. The color code was red-red-red and I plucked a red-red-orange (very subtle color difference) from the stash. The wrong resistor meant that we worked upward on the complexity scale to--yes--a transistor replacement. But that didn't fix it, of course, since the problem was still the resistor. My advisor said to go back and check resistances again. That is, start at the beginning.

Lessons? Check resistances with the ohmmeter if there's any doubt about color, or maybe just anyway. Start with simple checks to make sure the cheap parts are OK. As Greg says, rustle up a schematic. Even if you don't grasp the full electronic circuit significance, at least you'll be able to ID parts and know their designed values.

Chris Campbell

[1922VV111]

When I was a kid, dealing with tube stuff, I always assumed that the problem was a tube. Often not that.... Always look for the simplest explanation or the most common device, like bad switch contacts or capacitors that have gone south.

I recently diagnosed and repaired a Heath receiver with one channel out. I had great help online from a very knowledgeable guy across the country who had written an article about a similar device. I actually found the problem early on, a bad resistor, a 5-cent part. But I replaced it with a mistaken one. The color code was red-red-red and I plucked a red-red-orange (very subtle color difference) from the stash. The wrong resistor meant that we worked upward on the complexity scale to--yes--a transistor replacement. But that didn't fix it, of course, since the problem was still the resistor. My advisor said to go back and check resistances again. That is, start at the beginning.

Lessons? Check resistances with the ohmmeter if there's any doubt about color, or maybe just anyway. Start with simple checks to make sure the cheap parts are OK. As Greg says, rustle up a schematic. Even if you don't grasp the full electronic circuit significance, at least you'll be able to ID parts and know their designed values.

Chris Campbell

Learning how to use a multimeter and read a schematic and Solder is on my list next to learning how to develop film photos and learning how to fix a 8-track tape without the tape unspooling on me.

[electra225]

I have some old books I was fixing to toss. How to read schematics, how to use test equipment, books like that. Perhaps a good method would be for you to get a piece of test equipment, then we could have a discussion about how to best utilize it. There may be several differing opinions on how to best proceed, but this is a really good way to learn. A schematic may be considered simply as a road map of how electricity flows thru the device under test, what components affect current flow, then gives their locations in the circuit. You use a multimeter, set on voltage, to measure voltage at different points in the circuit in order to find faults. Then you replace a defective component, test again and note the difference in operation. I have been doing this for probably 40 years as a hobbyist, but I learn something almost every day and have experiences working on this old stuff I haven't had before. You never quit learning. Don't feel embarassed about maybe not having the knowledge more experienced hobbyists have. We all started like you are, from square one. I was fortunate to have a stepdad who had a TV repair shop and taught me a lot. The rest I pretty much learned the hard way......

[1922VV111]

I have some old books I was fixing to toss. How to read schematics, how to use test equipment, books like that. Perhaps a good method would be for you to get a piece of test equipment, then we could have a discussion about how to best utilize it. There may be several differing opinions on how to best proceed, but this is a really good way to learn. A schematic may be considered simply as a road map of how electricity flows thru the device under test, what components affect current flow, then gives their locations in the circuit. You use a multimeter, set on voltage, to measure voltage at different points in the circuit in order to find faults. Then you replace a defective component, test again and note the difference in operation. I have been doing this for probably 40 years as a hobbyist, but I learn something almost every day and have experiences working on this old stuff I haven't had before. You never quit learning. Don't feel embarassed about maybe not having the knowledge more experienced hobbyists have. We all started like you are, from square one. I was fortunate to have a stepdad who had a TV repair shop and taught me a lot. The rest I pretty much learned the hard way......

Is there any special voltage meter or soldering iron that's recommended? I have a few of them but I hear you got to get a good one that does it right. What I need to do is get a few kits to get the hang of it.

[Doug]

If you post the schematic then we can help u with trouble shooting. That's one way of learning.

Another way find some local ham or antique radio clubs in your area. They have meets and fests. Go there and talk to them.uou may find someone to help u learn.

Doug

[electra225]

I like using a VTVM, vacuum tube volt meter, but they need warmup time and can be clunky to maneuver. They are the most accurate and you don't have to watch the meter like you do with digital and the reading doesn't jump around like digital. I will admit to liking digital for reading resistance. I fried my favorite digital meter, so I'm down to just VTVM's. I have six on the bench I run all at the same time. I like about a 30-watt soldering iron.

[William]

I too use both types of measuring instruments for the same reasons as Greg. I have a soldering station, it has variable heat settings

Bill

[TC Chris]

I inherited my great-uncle John's Heath soldering station. I've never used it because (1) the tip is kinda clunky and (2) I have no ideas which heats work for what jobs. My usual devices are my classic "Weller Junior" one-temp soldering gun, which I got around 1958, and a Radio Shack soldering pencil.

So Bill, what is the technique for using variable-heat devices?

Chris Campbell

[William]

I am not sure I have a technique, Chris, but lets say you have a large chunk of solder holding a bunch of wires (common ground) to the chassis and you want to look original so you need to melt it. A low watt device will take forever to melt that. With a soldering station you can increase the heat and get the job done faster. Same goes in the other direction, low heat, when you want to solder on a PC board.

My first soldering device, that I received when I was in High School, was a Weller soldering gun. I still have it and still use it but when I started my retirement hobby I wanted something that was less clunky/heavy so I bought the Weller soldering station.

Bill