0

Old capacitor identification

Img 2318
Help out Hyratel in the forums (post a comment here, Google+ or in our forums!)

I’ve been recently poking around an old stereo receiver, and have determined that the phono preamp is completely dysfunctional. now, this is ’70s era tech, and fairly high-end for the time. I need help identifying the construction and possible replacements for the capacitors on the preamp module.


Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.

Join 8,500+ makers on Adafruit’s Discord channels and be part of the community! http://adafru.it/discord

CircuitPython – Python on Microcontrollers is here!

Have an amazing project to share? Join the SHOW-AND-TELL every Wednesday night at 7:30pm ET on Google+ Hangouts.

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Follow Adafruit on Instagram for top secret new products, behinds the scenes and more https://www.instagram.com/adafruit/


Maker Business — Rethink Robotics closes shop. Long live collaborative robots #makerbusiness

Wearables — Cleaning is key

Electronics — Serial overkill

Biohacking — Biohacking Resources – Books, Talks and Podcasts

Python for Microcontrollers — CircuitPython @ Hackaday SuperCon #ICYMI @circuitpython @micropython @ThePSF #Python

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at AdafruitDaily.com !



5 Comments

  1. They look like polypropylene film and foil type. These are pretty standard fair for a lot of audio stuff, because the frequency characteristics are generally pretty good.

  2. I would replace any electrolytics and see if that fixes it. Those poly caps hold up fairly well.

    For more info on restoration, check around the radio collector web sites like:
    http://groups.yahoo.com/group/thetransoceanicfanatic/

  3. Polystyrene and foil construction capacitors.

  4. The tubular caps with the clear ends are polystyrene and foil. They are good quality and should be good as new. They are VERY heat sensitive so be careful if you solder near them. If you still want to replace them, there value in pF is printed on the part and you can use a mylar or polpropylene. If the polystyrene caps are used in a resonant circuit with an inductor with a ferrite core, the temperatur coefficiant of the cap cancels out the temperature coefficient of the ferrite core. You have to be careful replacing caps in those circuits. In your phono preamp, there will not be resonant circuits, so this will not be an issue.

  5. Yes, polystyrene. Although generally a high quality capacitor as described, I’ve replaced some in audio equipment. Shorted or mechanically intermittent.

    Came across my first ones in a Heathkit AR-15 stereo receiver nin 1966.
    It was ahead of its time with crystal IF filters, fets, ics.

Sorry, the comment form is closed at this time.