Wurlitzer 1650 Jukebox - No filaments
Bill Heronemus
various different filament voltages as in 5U4, 6L6, 12AX7, 6J5, etc., I wonder
if it is wired in series and could be a defective tube causing this problem.
Otherwise, I will need a schematic to trace it out. Where might I find this
material? I have looked thru the FAQ's and come up empty so far. Thanks,
Bill
BOB URZ
Look up the tube types and find out what pins the filaments are on. Then, you can
trace back from there. It would also be helpful to know what ac voltages you are
getting out of the power transformer. The tube manual will give you approximate
voltages for a push pull output stage for the type of tubes you have.
BOB
Irving Bush
the power transformer.
The rest of the tubes will be have their heater voltages from the 6v
winding. The 12AX7 will have its heater pins connected in parallel. i.e. the
two outer pins connected together to one side of the heater winding, and its
center-tap to the other side.
Do the tubes light up?
Be careful working on tube equipment - the high voltages will be in the
order of 200v or more.
Irving
"Bill Heronemus" <n3...@aol.com> wrote in message
news:20010704195448...@ng-ce1.aol.com...
John Robertson
connection at the first tube's terminals. Does the machine work? If it
starts up and pops a record onto the turntable then the 5U4 should
light up at that point. normally on jukes the regular tubes are kept
hot and only the 5U4 was turned on/off when a record was playing, this
allowed for fast audio, yet low heat when the b+ was shut down, the
tubes would last for years with only their filaments warm...
We sell schematics by the way.
There is a jukebox newsgroup as well alt.collecting.juke-boxes
John :-#)#
CLSNOWYOWL
filament voltages for the tubes. These really pack a lot of power, so be very
careful when checking caps. also look for poor insulation, cold, clumpy solder,
etc...
Subject: Re: Wurlitzer 1650 Jukebox - No filaments
From: John Robertson j...@flippers.com
Date: 7/5/01 1:57 AM EST
Message-id: <qj38ktkt0cs6k6upl...@4ax.com>
Gerhard Grass
If you need a "best friend" for your tubes, try this link:
http://www.frank.nostalgiaair.org/
I hope it helps!
Gerhard
BOB URZ <so...@inetnebr.com> schrieb in im Newsbeitrag:
3B43AFE6...@inetnebr.com...
Lenny
capacitors for tube filaments? What kind of a circuit is that??
Just as a point of information though, some of the old Wurlitzers used a
bi metalic "surgistor". It was designed to blast the 6volt heaters with
9volts on startup and just about the time the B+ came up the bimetal
would bend and switch the filament voltage to 6volts. The amp would warm
up in 7 seconds as I recall, but boy did those tubes shine on powerup.
Lenny Stein.
CLSNOWYOWL
typo.
Subject: Re: Wurlitzer 1650 Jukebox - No filaments
From: Lenny captain...@hotmail.com
Date: 7/5/01 3:56 PM EST
Message-id: <3B44D4...@hotmail.com>
Bill Heronemus
>bi metalic "surgistor". It was designed to blast the 6volt heaters with 9volts
on startup and just about the time the B+ came up the bimetal would bend and
switch the filament voltage to 6volts. The amp would warm up in 7 seconds as I
recall, but boy did those tubes shine on powerup.
>Lenny Stein.
>
Thanks Lenny and all. You've given me enough information to get started at
least. Since none of the tubes are lit, I'll check the power transformer
(didn't have a VOM with me last time) and look for that bi-metal, although I
probably would have noticed that by now. Hopefully it's just a resistive fuse
dropping the primary voltage.
Since nothing mechanical is working besides the platter motor turning it will
probably still be a challenging project for me. Will keep you posted on what I
find out.
Bill Heronemus
Tom Woodrow
filaments off when there was no activity. Once the amp was required, power was
applied and a full 12 volts was sent to all of the tube filaments for quick warmup.
This was controlled by a relay whose coil was in the output tubes cathode circuit.
When cathode current was sufficient, the relay closed and the filament voltage was
dropped to 6.3V.
Tom Woodrow
John Robertson wrote:
> No filaments? Then the main transformer is out or you have a broken
> connection at the first tube's terminals. Does the machine work? If it
> starts up and pops a record onto the turntable then the 5U4 should
> light up at that point. normally on jukes the regular tubes are kept
> hot and only the 5U4 was turned on/off when a record was playing, this
> allowed for fast audio, yet low heat when the b+ was shut down, the
> tubes would last for years with only their filaments warm...
>
> We sell schematics by the way.
>
> There is a jukebox newsgroup as well alt.collecting.juke-boxes
>
> John :-#)#
>
> On 04 Jul 2001 23:54:48 GMT, n3...@aol.com (Bill Heronemus) wrote:
>
> ?I was wondering if anyone had any information on this creature. Since it uses
> ?various different filament voltages as in 5U4, 6L6, 12AX7, 6J5, etc., I wonder
> ?if it is wired in series and could be a defective tube causing this problem.
> ?Otherwise, I will need a schematic to trace it out. Where might I find this
> ?material? I have looked thru the FAQ's and come up empty so far. Thanks,
> ?Bill
Tom Woodrow
bad none of the tubes may be getting filament voltage.
Tom Woodrow
Lenny
amps in my attic. I stripped them from an old box I canabilised around
1960. Among others they used a pair of 6L6's in the output and a 5 pin
tube with a grid cap for a preamp. The rectifier was a 5Z3 and if I
recall and the plate voltage was a whopping 1100 volts. You want to be
real careful around this baby.
Now that I've shaken the cobwebs out somewhat I recall that the
surgistor arrangement was used on the 35watt Eico stereo power amp which
I built as a kid from a kit in the 60's. It sported 4 EL34's, 2 6SN7's,
and a 12AX7 as a preamp. In an effort to keep hum and noise down, they
utilised a novel filamet arrangement. The 12AX7 filament was part of one
of the two output tube's cathode circuit. As the EL34's heated up and
their cathode bias was being establised, so did the 12AX7 filament, and
with DC! Amplifier warmup took about 90 seconds and it seemed to work
fairly well. I also think that it may have provided a sneaky source of
negative feedback too but I'm not certain.
I still pull that amp out every now and then and fire it up, for old
time sake. I just can't seem to throw anything away, to the absolute
dismay of my poor wife..... Lenny Stein.
Tom Woodrow
Thet plate cap tube must have been a 6J6.
Just curious, what amp is that. I don't recall one with a 1100vdc B+. Is this one with
the field coil speakers (5200 ohm across the b+)?
We used to take these amps ansd soup them up. We used to get them without tubes. A set
of tubes then eas about $10. We put in 6L6GC's, replaced all the caps (by then they
were almost 13 years old) replace the power transformers with ones from old TV chassis
and new PP output transformers (50W) that we used to get from Olsen Electronics for
$5.
We even figired out a way to repair the 15" field coil speakers. We must have rebuilt
20 of these amps. We were even selling them to local rock bands as bass guitar amps.
It was great. WHen the bands broke up, we would get the amps back at a fraction of the
cost and then resell them to the next band.
Life was wonderful in high school.
Tom Woodrow
Lenny
them. I don't think I ever had the speakers. I may have installed a
choke in place of the field and used a pm speaker. The amplifier model
as I recall was 850. I have the schematic around here somewhere too. It
was a long time ago.... Lenny Stein.