Gentner DH20 digital hybrid (telephone balance unit) not outputting to phone line
Tony Whitmore
which isn't outputting to the phone line. I'm believe these models are
now made by Comrex and are generally thought of as reliable!
I have reset all the pots to mid-values and the DIP switches are all
set to the defaults. I can use a POTS handset through the unit OK.
According to the manual the "On" light on the DH20 is supposed to
flash when the phone is ringing, which it doesn't do. Manually
connecting the DH20 by pressing the "On" button disconnects the POTS
handset as it is supposed to, although the switch does not respond
quickly and seems to require some pressing to engage.
Audio from the mixer flashes the "Send" and "Caller" LEDs. I'm not
sure whether this is correct (although just the "Send" LED flashing
would make more sense to me.) No audio is heard at the remote end of
the phone line though, so it doesn't seem as if audio is being passed
out to the phone line. Monitoring on the mixer when connecting the
call, you can hear the line being connected to (a short couple of
clicks, which seems to be characteristic of hybrids).
Audio from the phone line doesn't register with the unit at all. When
disconnecting, the DH20 refuses to hang up, requiring a hard power
reset. When the power is pulled, the call is resumed on the POTS
handset as it is supposed to be.
It seems likely that there's a fault with the circuitry which sends
the signal to/from the phone line, and possibly the switching panel.
My question is whether any one else has had similar problems and found
a solution. If the solution is a repair place, can anyone recommend
one? :)
The only other thing I can think of is that the phone line also has an
ADSL signal on it. There are known good microfilters in place however
so this shouldn't be disrupting the signal that the DH20 receives.
TIA,
Tony
Scott Dorsey
>Hi, I have a Gentner DH20 digital hybrid (aka telephone balance unit)
>which isn't outputting to the phone line. I'm believe these models are
>now made by Comrex and are generally thought of as reliable!
1. Did it work before?
2. Is it set up for UK phone lines?
>Audio from the mixer flashes the "Send" and "Caller" LEDs. I'm not
>sure whether this is correct (although just the "Send" LED flashing
>would make more sense to me.) No audio is heard at the remote end of
>the phone line though, so it doesn't seem as if audio is being passed
>out to the phone line. Monitoring on the mixer when connecting the
>call, you can hear the line being connected to (a short couple of
>clicks, which seems to be characteristic of hybrids).
Is it taking the phone off-hook at all? You hear the click, but is the
hybrid drawing current off the line?
>Audio from the phone line doesn't register with the unit at all. When
>disconnecting, the DH20 refuses to hang up, requiring a hard power
>reset. When the power is pulled, the call is resumed on the POTS
>handset as it is supposed to be.
>
>It seems likely that there's a fault with the circuitry which sends
>the signal to/from the phone line, and possibly the switching panel.
>My question is whether any one else has had similar problems and found
>a solution. If the solution is a repair place, can anyone recommend
>one? :)
Could be all kinds of stuff including the line protection circuitry
on the front end. ClearOne or CircuitWerkes should be able to get you
a schematic for the thing.
If it's intended for US lines, common mode ringing on UK phone lines
can blow the line protection stuff on some equipment.
If you want repair in the US, I would suggest CircuitWerkes.
>The only other thing I can think of is that the phone line also has an
>ADSL signal on it. There are known good microfilters in place however
>so this shouldn't be disrupting the signal that the DH20 receives.
This will just cause some noise.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Tony Whitmore
On Mar 27, 1:23 pm, klu...@panix.com (Scott Dorsey) wrote:
> 1. Did it work before?
Its a second hand unit, which was believed to have been working at the
time I got my hands on it. However, it has been in storage for a while
and this is the first time I've tried to get it up and running.
> 2. Is it set up for UK phone lines?
The unit was originally purchased in the UK and the manual says it's
compatible with UK standards.
> >Audio from the mixer flashes the "Send" and "Caller" LEDs. I'm not
> >sure whether this is correct (although just the "Send" LED flashing
> >would make more sense to me.) No audio is heard at the remote end of
> >the phone line though, so it doesn't seem as if audio is being passed
> >out to the phone line. Monitoring on the mixer when connecting the
> >call, you can hear the line being connected to (a short couple of
> >clicks, which seems to be characteristic of hybrids).
>
> Is it taking the phone off-hook at all? You hear the click, but is the
> hybrid drawing current off the line?
I'm not sure how to tell if it is drawing current off the line. It
certainly interrupts a call in progress and maintains the connection
when "On".
> >It seems likely that there's a fault with the circuitry which sends
> >the signal to/from the phone line, and possibly the switching panel.
> >My question is whether any one else has had similar problems and found
> >a solution. If the solution is a repair place, can anyone recommend
> >one? :)
>
> Could be all kinds of stuff including the line protection circuitry
> on the front end. ClearOne or CircuitWerkes should be able to get you
> a schematic for the thing.
There are some schematics in the manual, but it doesn't help me much
not being an electronic engineer. :) I've taken the lid off and there
are no visibly damaged components, no burnt-out chips etc.
Thanks,
Tony
Scott Dorsey
>> 1. Did it work before?
>
>Its a second hand unit, which was believed to have been working at the
>time I got my hands on it. However, it has been in storage for a while
>and this is the first time I've tried to get it up and running.
Okay, clean the hookswitch relay, before doing anything else. If it used
to work, and it has been in storage a long time and doesn't work, contact
corrosion is the first thing to worry about.
>I'm not sure how to tell if it is drawing current off the line. It
>certainly interrupts a call in progress and maintains the connection
>when "On".
If you can call someone, hang up the phone, pick it back up and they
are still there, then it's drawing current off the line and taking the
line off-hook.
>> >It seems likely that there's a fault with the circuitry which sends
>> >the signal to/from the phone line, and possibly the switching panel.
>> >My question is whether any one else has had similar problems and found
>> >a solution. If the solution is a repair place, can anyone recommend
>> >one? :)
>>
>> Could be all kinds of stuff including the line protection circuitry
>> on the front end. =A0ClearOne or CircuitWerkes should be able to get you
>> a schematic for the thing.
>
>There are some schematics in the manual, but it doesn't help me much
>not being an electronic engineer. :) I've taken the lid off and there
>are no visibly damaged components, no burnt-out chips etc.
Call your local broadcast tech!
Tony Whitmore
On Mar 27, 2:41 pm, klu...@panix.com (Scott Dorsey) wrote:
> Tony Whitmore <t...@tonywhitmore.co.uk> wrote:
> >Its a second hand unit, which was believed to have been working at the
> >time I got my hands on it. However, it has been in storage for a while
> >and this is the first time I've tried to get it up and running.
>
> Okay, clean the hookswitch relay, before doing anything else. If it used
> to work, and it has been in storage a long time and doesn't work, contact
> corrosion is the first thing to worry about.
I'm quite experienced with a bottle of contact cleaner! I'll clean the
various socket contacts, although the inside of the unit looked
pristine when I opened it.
> >I'm not sure how to tell if it is drawing current off the line. It
> >certainly interrupts a call in progress and maintains the connection
> >when "On".
>
> If you can call someone, hang up the phone, pick it back up and they
> are still there, then it's drawing current off the line and taking the
> line off-hook.
I'll test this ASAP.
> >There are some schematics in the manual, but it doesn't help me much
> >not being an electronic engineer. :) I've taken the lid off and there
> >are no visibly damaged components, no burnt-out chips etc.
>
> Call your local broadcast tech!
I don't have one, hence looking for recommendations for one!
Thanks,
Tony
mako...@yahoo.com
does it matter if the red and green may be reversed?
some phone gadgets don't like that, some don't care...
Mark
blackburst
You don't mention what is FEEDING the DH20, to cause audio to travel
back down the phone line to the caller. Normally, a mix-minus
(everything but the phone itself) is fed from a mixer to the DH20.
This is what the caller hears.
So you have to set a send level on the mixer, both individual channels
and a sub/aux master, and also insure that the DH20's input level is
set correctly.
Are you by any chance expecting the POTS hanset to feed back down the
line? It won't.
Tony Whitmore
On Mar 27, 3:43 pm, makol...@yahoo.com wrote:
> does it matter if the red and green may be reversed?
>
> some phone gadgets don't like that, some don't care...
Red and green being the two cores on the phone line? (Excluding the
bell wire, I guess.) I think they're blue and white in the case of
this particular socket!
Tony
Tony Whitmore
I mention the audio set up above, but to clarify: A microphone is
connected to the mixer. An aux output with this microphone channel
present is connected to the SEND socket of the DH20. This is what
should be sent out down the phone line. The cables are known good and
the "signal present" LEDs flash on the DH20 when the microphone is
spoken into.
The output of the DH20 is connected to the input of another channel.
Both these channels are then monitored via cans. The signal from the
DH20 is *not* fed into the aux output.
So this very simple set up creates a mix-minus via the use of the aux
output.
> So you have to set a send level on the mixer, both individual channels
> and a sub/aux master, and also insure that the DH20's input level is
> set correctly.
The signal from the microphone/mixer is good and registers well on the
"signal present" LEDs. The input potentiometers are set to mid values.
> Are you by any chance expecting the POTS hanset to feed back down the
> line? It won't.
No, I'm not expecting that. All I'm trying to do is get the aux output
sent down the line and the voice from the other end of the line fed
back into the mixer.
Thanks,
Tony
mako...@yahoo.com
yes that is what I mean...you might try reversing them
Mark
WillStG
OK Tony, when you say "all the dip switches are set to defaults"
what does that mean exactly? What about the dip switches behind the
front panel? When you say it works with a POTS line, you mean you
can call both out and in and have a conversation off air?
When the phone rings, you have tried pressing the "on" button on
the front panel, then trying to talk to the caller through the console
from a studio mic? And are you also trying to hang up from the DH20's
front panel? When you say it will not drop a call, do you mean when
the caller hangs up it is stuck with line seized, or will it drop the
call when the caller hangs up? Your lack of specificity makes me
wonder how you are operating the unit, and what your dip switch
settings are.
But if it's not an operational issue, to troubleshoot no audio on
the "Caller Out" give a listen to the DH20's "aux output": The aux
out should provide you either a mix or just caller audio depending,
but you must have the automatic Mix Minus function disabled. Make
sure that's disabled. Also try listening to the "monitor out" with a
speaker or headphones. The "Caller Out" is an XLR output and if
someone plugged it into a console mic input with 48 volts active it is
possible that the output is blown, maybe. If the other ports work,
you can use the Aux out instead and have your maintenance guy fix the
XLR outs later.
Also make sure the phone lines you are using are supplying power
and are not "Dry lines". The unit won't work with dry lines. If you
need support, Comrex owns the rights to the DH20. Personally I'd much
rather use a "Telos One".
Will Miho
NY TV/Audio Post/Music/Live Sound Guy
"The large print giveth and the small print taketh away..." Tom Waits
Tim Perry
"Tony Whitmore" <to...@tonywhitmore.co.uk> wrote in message
news:35d08539-41b4-4fa3...@o36g2000yqh.googlegroups.com...
> Hi, I have a Gentner DH20 digital hybrid (aka telephone balance unit)
> which isn't outputting to the phone line. I'm believe these models are
> now made by Comrex and are generally thought of as reliable!
>
> I have reset all the pots to mid-values and the DIP switches are all
> set to the defaults. I can use a POTS handset through the unit OK.
> According to the manual the "On" light on the DH20 is supposed to
> flash when the phone is ringing, which it doesn't do.
Check fuse F2 inside the unit. This connects the tel line to the ring
detect circuit.
Inspect circuit board for burnt parts or traced and repair as needed.
You have the manual but it can be seen here
http://www.kilpack.com/DH20DH22UserManual.pdf
Tony Whitmore
On 28 Mar, 21:42, "Tim Perry" <timpe...@donespameroadrunner.com>
wrote:
>
> Check fuse F2 inside the unit. This connects the tel line to the ring
> detect circuit.
Fuse F2 doesn't exist, but I think that's only supposed to be present
in the DH22, the two line version of the unit. I have the DH20, and F1
is the only fuse I can see on the PCB:
http://tonywhitmore.co.uk/misc/SP_A0204.jpg
http://tonywhitmore.co.uk/misc/SP_A0206.jpg
The F1 fuse is OK, passes a continuity check from a multimeter.
> Inspect circuit board for burnt parts or traced and repair as needed.
No burnt or damaged parts that I can see. Whole thing looks nice and
clean.
Tony Whitmore
> > If you can call someone, hang up the phone, pick it back up and they
> > are still there, then it's drawing current off the line and taking the
> > line off-hook.
>
> I'll test this ASAP.
I tested it and the DH20 does seem to be "off-hooking".
Tony Whitmore
On 28 Mar, 19:56, WillStG <will...@aol.com> wrote:
> OK Tony, when you say "all the dip switches are set to defaults"
> what does that mean exactly? What about the dip switches behind the
> front panel?
I'm referring to the dip switches behind the front panel. They seem to
be the only ones on the unit (certainly the only ones detailed in the
manual).
> When you say it works with a POTS line, you mean you
> can call both out and in and have a conversation off air?
Yes, the POTS handset connected to the "set" jack works fine. I can
make and receive calls and I can hold conversations using the POTS
handset.
> When the phone rings, you have tried pressing the "on" button on
> the front panel, then trying to talk to the caller through the console
> from a studio mic?
That's exactly the setup I've got and that I can't get working. All
autoanswer detection is turned off. According to the manual the "on"
light is supposed to flash when the line rings, but this does not
happen. If I press (and hold!) the "on" button when someone is ringing
the line, the DH20 picks up the line (off-hooks) but there's no audio
to/from the line.
> And are you also trying to hang up from the DH20's
> front panel?
Yes, using the "Off" button.
>When you say it will not drop a call, do you mean when
> the caller hangs up it is stuck with line seized, or will it drop the
> call when the caller hangs up?
The remote caller's line does not stay "seized" if the remote caller
hangs up on a connection to my DH20, at least in my tests. However the
unit's "on" light stays lit, even when pressing and holding the "off"
button. The local POTS handset (studio handset) is not able to access
the line, so the local line is "seized". Anyone else trying to call
the local line when the unit is in this condition receives a "busy"
tone.
> Your lack of specificity makes me
> wonder how you are operating the unit, and what your dip switch
> settings are.
Just to repeat, all the dip switches are set to "off". All automatic
answer settings, automatic mix-minus settings etc. are disabled. I am
manually pressing the "on" and "off" buttons as necessary. I'm going
for the simplest possible set up. Mic->Mixer->Aux output -> DH20 ->
phone line.
And back again:
Phone line -> DH20 -> mixer channel -> Main output & Monitors.
Basically the simplest example given in the manual. :)
> But if it's not an operational issue, to troubleshoot no audio on
> the "Caller Out" give a listen to the DH20's "aux output": The aux
> out should provide you either a mix or just caller audio depending,
> but you must have the automatic Mix Minus function disabled. Make
> sure that's disabled.
Automatic mix-minus is definitely disabled. There's no output from the
aux output either, when testing a remote caller, unit showing "on".
> Also try listening to the "monitor out" with a
> speaker or headphones.
Nothing on the monitor output with a remote caller, unit "on" either.
Tested with headphones.
> The "Caller Out" is an XLR output and if
> someone plugged it into a console mic input with 48 volts active it is
> possible that the output is blown, maybe. If the other ports work,
> you can use the Aux out instead and have your maintenance guy fix the
> XLR outs later.
There's no output on any of the ports, so it doesn't look like any one
output is faulty.
> Also make sure the phone lines you are using are supplying power
> and are not "Dry lines".
"Dry lines" seems to be a US term, but the line currently connected to
this DH20 is a normal UK POTS line (analogue, copper). It supplies
power to devices with a REN of up to 4. (I have tried another line and
got the same results as with this line.)
> The unit won't work with dry lines. If you
> need support, Comrex owns the rights to the DH20.
The unit is out of warranty, but I have found a couple of Comrex
resellers here in the UK. I'm not familiar with any of the companies,
so I'd welcome recommendations from members of this newsgroup for UK-
based Comrex repair agents.
> Personally I'd much
> rather use a "Telos One".
If you have one spare you would like to send me, that would be
great. ;)
Thanks for your thoughts!
Tony
WillStG
> The unit is out of warranty, but I have found a couple of Comrex
> resellers here in the UK. I'm not familiar with any of the companies,
> so I'd welcome recommendations from members of this newsgroup for UK-
> based Comrex repair agents.
Well Tony, sounds like you have it covered. The UK distributor for
COMREX is
Vortex Communications
http://www.vtx.co.uk
Tel: 44 (0)20 8579 2743
Fax: 44 (0)20 8840 0018
In the US, even out of warranty, COMREX says they offer "free
upgrades and evaluations of current products." The DH20 is mentioned
on the same page as a current product, they purchased the "product and
support" from Gentner.
http://www.comrex.com/support/technotes/tn231.htm
Here they are pretty good about talking you through a problem on
the phone, so you might call US support if your UK distributor won't
help you. They also say if you have a serial number they may have a
repair log on a unit; some gear for example damaged by lightning
strikes get flagged as "unrepairable".
As for the line not dropping, disconnect the phone line when
latched and see what happens. If the line drops at least that part of
the problem is likely with the phone lines (the phone company loop
drop being too short for the DH20 to recognize it), if not the problem
is definitely with the unit. I might try flipping the dip switches
around and see what happens as well. Hey, maybe up and down are
reversed or something. And of course, plug and unplug the power a few
times, reseat any connectors, the usual maintenance first line of
repairs stuff.
Best,
Will Miho
NY TV/Audio Post/Music/Live Sound Guy
"The large print giveth and the small print taketh away..." Tom Waits
"The large
Tony Whitmore
> On Mar 29, 12:49 pm, Tony Whitmore <t...@tonywhitmore.co.uk> wrote:
> Well Tony, sounds like you have it covered. The UK distributor for
> COMREX is
>
> Tel: 44 (0)20 8579 2743
> Fax: 44 (0)20 8840 0018
Yes, I rather thought it was headed towards a repair bill!
> As for the line not dropping, disconnect the phone line when
> latched and see what happens. If the line drops at least that part of
> the problem is likely with the phone lines (the phone company loop
> drop being too short for the DH20 to recognize it), if not the problem
> is definitely with the unit. I might try flipping the dip switches
> around and see what happens as well. Hey, maybe up and down are
> reversed or something. And of course, plug and unplug the power a few
> times, reseat any connectors, the usual maintenance first line of
> repairs stuff.
Hadn't tried pulling the phone line whilst the unit is "on" or
randomly flipping dip switches yet. :)
I will post back as/when I have some more info.
Tony
arv...@gmail.com
Scott Dorsey
>hi i have gentner dh20 can you please help when i try to put on air the caller the on air button doesnt work.. when i press it it on for a second then turn back to off but the line is ok, i think its on the gentner please help thanks...
a dial tone?
If you have a telephone plugged into the line and you pick it up and listen,
then you bring the caller on with the gentner, do you hear it click?
If you disconnect the gentner from the board and just plug in headphones to
the console in, then short the remote control pins to make it go off-hook,
does it go off-hook?
Was it working before and somebody played with the dip switches by any
chance?
There is a lot more to go wrong with the DH20 than with a conventional
analogue hybrid. But there is also a lot more configuration stuff required
too.