Discussion in 'General Technical Questions and Answers' started by K8MOT, Jun 13, 2021.

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  1. K8MOT

    K8MOT Ham Member QRZ Page

    I just had a very bad experience with Astron power supply people. I wanted to replace the main filter cap in my VS-50M power supply. I emailed them for availability of the 2200 MDF 35 volt screw terminal cap. They sent a photo of the wrong cap, wrong size, wrong values. I sent them the part number (C1) 220 mfd 35 volt for the VS_50M, they asked if i could give more information, I sent them a photo of the interior with a arrow pointing to the cap, they needed more info, I sent them the diagram with the part outlined. This is a large screw terminal computer grade cap, They sent me a photo of a 10,000 mfd, 25volt radial lead cap about the size of your little finger. after 10 or so emails i determined the were just screwing with me. Why would they do that ? By the way, if anyone could supply the right or even close cap i would greatly appreciate the help.
  2. K1APJ

    K1APJ XML Subscriber QRZ Page

    I wouldn't call C1 the main filter cap, are you sure you aren't looking for C5? C5 is a pair of 50,000 uF 25 VDC caps.
    WA9SVD likes this.
  3. WA9SVD

    WA9SVD Ham Member QRZ Page

    Astron has changed parts in their supplies over the years, depending on availability. "Screw-type" caps are difficult to find any more, so they HAVE changed component styles, while still retaining the same spec. How old is your power supply? (And be SURE you are describing the component in question properly. I have never had a problem with Astron tech service.)
    KA0HCP likes this.
  4. AG6QR

    AG6QR Premium Subscriber QRZ Page

    They may have been confused with your use of abbreviations for megaFarads and milliFarads. Not sure what the main capacitor of the VS-50 is, but I know my RS-35 uses a main capacitor of 64,000 microFarads, which can be written as 64,000 uF, 64 mF, or even 0.064 F.
    KA0HCP likes this.
  5. KA9JLM

    KA9JLM Ham Member QRZ Page

    So is it 220 or 2200 uF that you need ?
    KA0HCP likes this.
  6. K8MOT

    K8MOT Ham Member QRZ Page

  7. WA9SVD

    WA9SVD Ham Member QRZ Page

    You are right, thereISs something wrong. In the VS-50 schematic, C5,( the MAIN filter capacitor) "screw-type" cap is 64,000 µF or 70,000 µF (MICROfarad!) (Often abbreviated "64K/25 Volt"or "70K/25 Volt" in the schematic.) C1 IS A 2200 µF capacitor that apparently is soldered on the regulator board itself. That alone would have Astron "scratching their head," trying to understand which capacitor is referred to. Not sure where a "220 µF capacitor is involved, but it certainly is NOT a "screw-type" capacitor.
    It is necessary to be VERY specific and accurate if Astron is to help; if the supply is already opened up and/or partly disassembled, it shouldn't be too difficult to properly identify which part (or parts) are needed. (Often, the parts needed are "off the shelf" ' available from Mouser, DigiKey, Jameco, Allied, Newark, or other parts vendors; they don't HAVE to be obtained from Astron.)

    Hint: You CAN substitute a higher voltage rated capacitor for what is specified, IF of similar physical size/shape, but NEVER a lower working voltage cap. (I.e. you can use a 2200 µF 35 Volt cap in place of a 2200µF 25 Volt cap (if it fits physically, that is) but NEVER use a 16 Volt capacitor to replace a 25 Volt cap!
  8. WA9SVD

    WA9SVD Ham Member QRZ Page

    o_ONever heard of "megaFarads or "milliFarads." Where did you find those designations? (and a :eek:MEGA-FARAD? :confused: I don't think that cap would fit in a VS-50, much less the house it is in.:rolleyes:) I've never even seen "0.064 F(arad.")
    WB5THT likes this.
  9. KA9JLM

    KA9JLM Ham Member QRZ Page


    Can get confusing.

    Is the cap in question bad, Or being changed just for grins ? :D

    I would use a O-Scope and check the ripple, Before replacing a good part.

    For that supply, The Variable voltage adjustment pot would be my first replacement. Fixed resistors work more better for a station supply.
    Last edited: Jun 13, 2021
  10. WG7X

    WG7X Platinum Subscriber Platinum Subscriber QRZ Page

    As a long time repair tech, I can say with some certainty that customers are not always right, especially when it comes to trying to diagnose problems over the phone. I feel sorry for my companies tech support weenies: they have to try and filter out the gibberish from someone who is usually too inexperienced to fix something themselves. (Or to send in a failed piece) I recently had a failure of a amplifier here. I'm not trained/ experienced / or have enough spare parts to even begin to work on this complicated amp, so I'm gonna send it in...

    I realize my shortcomings: But it would never even occurred to me to get on QRZ and begin bashing the amp company. It would not make a difference and it might just hinder me getting a good repair.

    If I had a dime for every customer who just said: "It's broke; send someone yesterday!!" I could have retired years ago!o_O
    W4NNF likes this.

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