Marantz 4400 CRT replacement by 2bp1
- Thread starter novanec
- Start date
CIR Engineer
What?
Could you please provide the pinout for this tube (5LO38M)? I have one and would like to use it.Zillandia,
The pinout spec's I thought you referred to was the pin# and internal connection.
The blue phosphor CRT is a Russian tube 5LO38M. Very difficult to locate these days. Found mine after an arduous Internet search.
camman
Thank you,
craigr
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CIR Engineer
What?
Also, does anyone know if there is a RED phosphor tube that would work? I have been unable to find one. I think red could look really cool in my 2110 especially since there is the blue filter in front of it (should make magenta).
Does anyone know of any other blue phosphor scope tubes off hand? They are so much harder to come across than green!
craigr
Does anyone know of any other blue phosphor scope tubes off hand? They are so much harder to come across than green!
craigr
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Camman
Active Member
CIR Engineer
What?
Sweet thanks!
It may take me some time to sort that all out, but it should suffice.
Best regards,
craigr
It may take me some time to sort that all out, but it should suffice.
Best regards,
craigr
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CIR Engineer
What?
Got it thanks.
Really not bad at all.
craigr
Really not bad at all.
craigr
CIR Engineer
What?
Could you please tell me what socket the 5LO38M (and also the 2AP1) use? Radiomuseam says "11-pim magnal base," but I am still not sure what base that is...
http://www.radiomuseum.org/tubes/tube_cv790.html
Are these the right ones?
http://www.ebay.com/itm/370695558647?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
Or these?
http://www.ebay.com/itm/261597269329?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
I really would like to permanently mount the tube the right way with a socket, but I just want to be sure I get the correct one. I have heard they are difficult to find.
Thanks!
craigr
CIR Engineer
What?
...and what's the difference between a "Sub Magnal" and "Magnal" base? I know a lot about solid state, but little about tubes so I am somewhat out of my element here.
Thanks again,
craigr
Thanks again,
craigr
Camman
Active Member
Craigr,
Those are not the correct sockets.
I found the correct one РШ19 (RSH19), U11, Magnal, B11-1, B11-33, and B11-66 or IN-1 @
http://www.gstube.com
Not in stock although
Camman
Those are not the correct sockets.
I found the correct one РШ19 (RSH19), U11, Magnal, B11-1, B11-33, and B11-66 or IN-1 @
http://www.gstube.com
Not in stock although
Camman
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CIR Engineer
What?
THANK YOU THANK YOU THANK YOU!!!
Now I can stop pulling out what little hair I have left :yes:
That's what I assumed, but I didn't want a simple mistake to wind up costing me. So thanks again.
I just ordered the sockets you linked me to.
craigr
CIR Engineer
What?
So I thought this would be a quick project once all the parts were here, but instead I am pulling out my hair. I have two CRT's here; the 2AP1 and the 5LO38M. Both tubes appear to have identical pinouts so I have been doing all my testing with the 2AP1 in case something goes wrong.
Well, I cannot get any illumination out of the 2AP1 I have here. I don't know if the problem is my wiring pinout or if the 2AP1 I have is defective or dead. I am afraid to test with the 5LO38M because I certainly don't want to fry that one. The only thing I am certain of is that the heater is correct because it lights up properly.
Could you please check my wiring?
2AP1 Pin 1 Heater H1 = Marantz Pin 1
2AP1 Pin 2 Cathode K = Marantz Pin 3
2AP1 Pin 3 Deflection #1 D1 = Marantz Pin 7
2AP1 Pin 4 Anode #1 A1 = Marantz Pin 4
2AP1 Pin 5 No Connection
2AP1 Pin 6 Deflection #2 D4 = Marantz Pin 12
2AP1 Pin 7 Anode #2 A2 = Marantz Pin 5
2AP1 Pin 8 Deflection #2 = Marantz Pin 9
2AP1 Pin 9 Deflection #3 = Marantz Pin 11
2AP1 Pin 10 Grid #1 = Marantz Pin 2
2AP1 Pin 11 Heater H2 = Marantz Pin 14
Is that right or what? It looks like the polarity of the deflections may be the other way, or that maybe the X-Y deflections are backwards?
This is frustrating the heck out of me because it should not be difficult!
I put my 2AP1 on my Sencore CR7000 CRT analyzer and I am not getting any emissions on the tester. However, none of these scope CRT's are in the Sencore refrence book, so I may be hooking the tube up wrong to the tester as well.
Help please :scratch2:
craigr
CIR Engineer
What?
I have the original 50TB1 still installed in the Marantz tuner and it works so I would expect that everything is in order.
I found a post in google groups that shows a wildly different pinout than what novanec has in his first post for the conversion to 2BP1. I don't think the info on google is correct though?
https://groups.google.com/forum/#!topic/rec.audio.tubes/etPmtNYDFfU
The poster shows this:
That's not what my schematics for the 2110 show though either.
Thanks,
craigr
CIR Engineer
What?
Now you have me thinking though... I did not try the centering controls when I was testing the 2AP1. The centering controls are near the midpoint and this centers the trace on the original 50TB1. However, I wonder if it is possible that the trace needs such radically different centering offsets that perhaps my trace was not hitting the phosphor surface and just shooting off the face of the 2AP1. Do you think that is possible?
craigr
Camman
Active Member
Hi Craig,
Even though the connections look correct, I did not use a 2AP1 connected to my Marantz 4400.
I just used the pin layout to determine the matching connections of the 5LO38M. (They both have 11pins.)
Attached pictures of connections I used and adapter I constructed to maintain stock CRT socket.
Hope this helps.
Let me know!
Even though the connections look correct, I did not use a 2AP1 connected to my Marantz 4400.
I just used the pin layout to determine the matching connections of the 5LO38M. (They both have 11pins.)
Attached pictures of connections I used and adapter I constructed to maintain stock CRT socket.
Hope this helps.
Let me know!