ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Hello All,
I am doing a detector arm circuit upgrade for my Beogram 4002 recommended by Beolover, and the BC547 transistor I have measures a Hfe of 420. Rudy suggests that it be over 500 and a Hfe>500 type. I have looked at various parts distributors and found BC547 with Hfe>450 and with Hfe>800 but not ones rated Hfe>500. Will the Hfe>800 work or is there someone who knows where I can get a BC547 with Hfe>500? Probably not the most informed question.
John
Hi John,Did you check out this Beolover Blog post (from this year) where Rudy switched out to a different transistor?One thing his posts on this emphasize are the final waveform for the record detection sensor signal. Whether you use the Beolover fixed arm LED light source of an original incandescent lamp (from Martin), you should take a look at the quality of that sensor output signal. That will assure you that the sensor is operating in a good range.
-sonavor
I have decided to look at this on my BG4000 just for something to do....however it seems the 2N5089 is no longer manufactured...….anyone got a good equivalent that's available in the UK?
Craig
Hello John,
Thanks for pointing that out. I must have been looking at possibly an earlier blog post where Rudy had the Hfe>500 transistor specified. However the transistor he specifies the 2N5089 with an Hfe>400 is not available anywhere I can find but ebay. I searched all the usual suspects like Newark, Mouser, etc. Just ordered from ebay.
I have noticed that the middle lead of the trimmer resistor and one outside leg is used to replace the fixed resistor, is the other leas just trimmed off?
Thanks for your rely to my first post it pointed me in the right direction.
Yes, the extra leg isn't used. It can be bent out of the way or trimmed.I found the transistor on Mouser.
Hello Sonavor,
I replied to your post by my email but it does not show that got posted here, I hopefully you got my message and thanks for your follow up. Not sure where I went wrong with the Mouser search for the transistor on their website, I thought I found the transistor but that it would have to be ordered from the manufacturer with a long wait time. But Thanks!
The link I posted should take you directly to the Mouser ordering page for that transistor. It shows they have over 17,000 pieces in stock.I didn't receive any emails.-sonavor