Couple of BV135 questions

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lbcomms
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Re: Couple of BV135 questions

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Mouser have a Spanish site:

https://www.mouser.es/ProductDetail/Vis ... Y7ouuAldkg

https://www.mouser.es/ProductDetail/Vis ... YicA%3D%3D

Buying Chinese "not so common" components such as RF semiconductors, larger film resistors, ceramic caps, and electros is a gamble, sometimes you win, sometimes you lose...
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cb4ever104
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Re: Couple of BV135 questions

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lbcomms wrote: 02 Sep 2021, 13:18 Mouser have a Spanish site:
Hi Sue . Yes , I know they do , but it's €20 for the cheapest shipping .
Capture.JPG
I can't pay that . I'll try my luck with those Chinese ones and see how i get on .

Thx
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ch25
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Re: Couple of BV135 questions

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Damn, I live countryside, but within 30km radius I have 10+ shops I could go and buy those resistors and many more :)
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Re: Couple of BV135 questions

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ch25 wrote: 02 Sep 2021, 15:37 Damn, I live countryside, but within 30km radius I have 10+ shops I could go and buy those resistors and many more :)
Lucky you . Are you near Gdansk ? If so , then I might be over for some work related stuff soon .
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Re: Couple of BV135 questions

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Near Warsaw
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Re: Couple of BV135 questions

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lbcomms wrote: 02 Sep 2021, 13:18 sometimes you win, sometimes you lose...
Is there an easy way to check these parts Sue to see if they're genuine once they arrive ?

Thanks
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Re: Couple of BV135 questions

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We buy a lot of components from them and always hit the minimum needed to get free shipping, think it's about 50 dollars from memory.

To check if they are genuine, you'll need a meter (i.e. LCR meter) that can measure the inductance. If you haven't got an LCR, wire a few in series / parallel so the total resistance is between say 45 and 55 ohms, then connect them to the output side of a SWR meter. Transmit on AM or FM and measure the SWR, if it's over 1.5 you have the junk low frequency or wire-wound ones...
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Re: Couple of BV135 questions

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lbcomms wrote: 02 Sep 2021, 19:26 wire a few in series / parallel so the total resistance is between say 45 and 55 ohms, then connect them to the output side of a SWR meter. Transmit on AM or FM and measure the SWR, if it's over 1.5 you have the junk low frequency or wire-wound ones...
Great. I can do that. Thanks for the tip.
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Re: Couple of BV135 questions

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If you got 68 and 180 ohm resistors, paralleling one of each gives you 50 ohms. So just get a short length of coax with a PL-259 on one end and the two resistors connected in parallel at the other end. Measure ohms with a multimeter between the centre pin and shield, you should have about 47 to 51 ohms.

If you do, plug it into a SWR meter (or a radio with one inbuilt, accuracy is not critical for this test) and SWR should be very close to 1:1. If it's over 1.5 then you have the junk low frequency "non inductive" types, if it's 3 or higher they will be wire-wound types.
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Re: Couple of BV135 questions

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lbcomms wrote: 04 Sep 2021, 11:59 If you got 68 and 180 ohm resistors, paralleling one of each gives you 50 ohms
Thanks Sue . Actually I did the maths on it yesterday and came up with that scenario too :)

1/Rt = 1/68 + 1/180 = 49.35 , which is pretty close . They'll probably take a while to arrive , but I'll let you know how I get on .

Sammy
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Re: Couple of BV135 questions

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lbcomms wrote: 04 Sep 2021, 11:59 If you do, plug it into a SWR meter (or a radio with one inbuilt, accuracy is not critical for this test) and SWR should be very close to 1:1. If it's over 1.5 then you have the junk low frequency "non inductive" types, if it's 3 or higher they will be wire-wound types.
SWR is 1.2 on the radio's meter , so it looks as if my Chinese friends came through 🙂
IMG_20210925_112109_resize_2.jpg
Now I just need to fix and reassemble the thing 👍🙂

Sammy
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Re: Couple of BV135 questions

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Just a few photos to update this thread in case anyone else has to work on one of these .

My "before" picture of this front pcb wasn't pretty .

IMG_20210807_150924.jpg

Someone had been in there before . One of the tracks was fried too . I cleaned the pcb a bit and repaired the track .

IMG_20210925_160458.jpg

Here's a picture of the other side too , with the 2 resistors fitted . 68 at the bottom and 180 at the top .

IMG_20210925_155739.jpg

Just got to refit it and resolder the RF and other wires that were removed .

S.
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Re: Couple of BV135 questions

Post by cb4ever104 »

Edd200sx wrote: 31 Aug 2021, 14:02 18v
You sure it's 18V Edd ? I'm only getting 7V at the bulb .
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Re: Couple of BV135 questions

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cb4ever104 wrote: 25 Sep 2021, 09:26 SWR is 1.2 on the radio's meter , so it looks as if my Chinese friends came through 🙂
Winner - you got lucky with that one...
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Re: Couple of BV135 questions

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cb4ever104 wrote: 25 Sep 2021, 16:24
Edd200sx wrote: 31 Aug 2021, 14:02 18v
You sure it's 18V Edd ? I'm only getting 7V at the bulb .
I did one a while ago and measured it with a vm
It lit up fairly nicely
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