Tech Help: Tube Substitution - 5U4GB

Hi Guys,
I accidentally ordered a 5AU4 tube for the 5U4GB. I read in a tube
substitution list that the 5AU4 can be substituted for the 5U4GB.
What I'd like to know has anyone tried this and if so, did it work?
I'm using this in a Seeburg AY100U with the SHFA3 amp. It looks to me
[I'm a tube newbie by the way] that the only difference is the
filament voltage. Is that correct? Should I try to return the 5AU4
and get the correct 5U4GB? Thanks for your help.
Bob

Originally Posted by Corvette Bob

Hi Guys,
I accidentally ordered a 5AU4 tube for the 5U4GB. I read in a tube
substitution list that the 5AU4 can be substituted for the 5U4GB.
What I'd like to know has anyone tried this and if so, did it work?
I'm using this in a Seeburg AY100U with the SHFA3 amp. It looks to me
[I'm a tube newbie by the way] that the only difference is the
filament voltage. Is that correct? Should I try to return the 5AU4
and get the correct 5U4GB? Thanks for your help.
Bob

Hi Bob,

I would get the 5U4GB valves rather than having to do a work round.
There seems to be plenty for sale in the USA at dealers and on Ebay.

Regards
Alan Hood
ami-man
UK

Corvette Bob wrote:
Hi Guys,
I accidentally ordered a 5AU4 tube for the 5U4GB. I read in a tube
substitution list that the 5AU4 can be substituted for the 5U4GB.
What I'd like to know has anyone tried this and if so, did it work?
I'm using this in a Seeburg AY100U with the SHFA3 amp. It looks to me
[I'm a tube newbie by the way] that the only difference is the
filament voltage. Is that correct? Should I try to return the 5AU4
and get the correct 5U4GB? Thanks for your help.
Bob

Ask the dealer to exchange (plus and $$) tubes due to your mistake.
He/she will probably do that.

Way too much trouble to adapt the tube!

John :-#)#

--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

Hi Alan and John,
Thanks for your comments and I'll do that. I'm starting to rebuild
the selector and amp and don't need more work. As an old solid state
guy, I'm enjoying the new world of tubes and learning how they work.
Bob

In article
,
Corvette Bob wrote:

Hi Guys,
I accidentally ordered a 5AU4 tube for the 5U4GB.

Uh oh....



I read in a tube
substitution list that the 5AU4 can be substituted for the 5U4GB.

No! The filament current is .75 amp higher, for starters. I think the
pinout's different, too.

What I'd like to know has anyone tried this and if so, did it work?

I've never tried it. 5U4s are so common, and they generally don't go
bad. Why are you replacing yours? Unless it's physically broken, not
lighting up, or has a white, cloudy spot on the inside instead of
silver, chances are, it works.

I'm using this in a Seeburg AY100U with the SHFA3 amp.

Fun fun.

It looks to me
[I'm a tube newbie by the way] that the only difference is the
filament voltage.

Current. They're both 5 volts. The higher current of the 5AU4 can burn
out the power transformer

Should I try to return the 5AU4 and get the correct 5U4GB?

Yes. Actually, any 5U4 variety will work, though the GB might be
uprated slightly. Actually, unless yours is broken, I wouldn't replace
it, they tend to last a long long time.

On Feb 24, 1:08*am, Corvette Bob wrote:
Hi Guys,
* *I accidentally ordered a 5AU4 tube for the 5U4GB. *I read in a tube
substitution list that the 5AU4 can be substituted for the 5U4GB.
What I'd like to know has anyone tried this and if so, did it work?
I'm using this in a Seeburg AY100U with the SHFA3 amp. *It looks to me
[I'm a tube newbie by the way] that the only difference is the
filament voltage. *Is that correct? *Should I try to return the 5AU4
and get the correct 5U4GB? *Thanks for your help.
Bob

It is rare for a 5U4 to fail completely, but as the tube ages it's
output voltage (the B+)will drop . Check your voltage output and if it
is close to what the schematic says, let it rock on. Ray

Hi Phil and Ray,
I tested my 5U4 in a friends Hickok 6000A tester and it checked out
fine. BTW, it does still say RCA for Seeburg on the base. I had to
replace more than half of the existing tubes so when I saw a fairly
low price for the 5AU4, I figured why not. When I received it, I
tested it and noticed that the tester called for 7.5V on the filament
instead of 5V. That's when I knew something was different. A side note
testing the 5AU4. As I increased the "Power Line Adjustment" pot
to start the test, the neon fuse light turned on. That hadn't
happened for any of my previous tube tests. The test meter centered
on the "Line Test" position but I wasn't sure about continuing so I
stopped the test at that time. I'll check the voltage at you suggest
Ray, before I rebuild the selector and amp. Just to make sure, is the
B+ voltage around 365V ?
Thanks for all your help guys.
Bob

On Feb 26, 8:30*pm, Corvette Bob wrote:
Hi Phil and Ray,
* *I tested my 5U4 in a friends Hickok 6000A tester and it checked out
fine. *BTW, it does still say RCA for Seeburg on the base. *I had to
replace more than half of the existing tubes so when I saw a fairly
low price for the 5AU4, I figured why not. *When I received it, I
tested it and noticed that the tester called for 7.5V on the filament
instead of 5V. That's when I knew something was different. A side note
testing the 5AU4. As I increased the "Power Line Adjustment" pot
to start the test, the neon fuse light turned on. *That hadn't
happened for any of my previous tube tests. *The test meter centered
on the "Line Test" position but I wasn't sure about continuing so I
stopped the test at that time. *I'll check the voltage at you suggest
Ray, before I rebuild the selector and amp. *Just to make sure, is the
B+ voltage around 365V ?
Thanks for all your help guys.
Bob

The B+ for the output tubes is 370V per the schematic Ray