HP10544a Technical Info needed
I am constructing a GPS disciplined OCXO using an HP10544a. If someone
has a copy of the HP manual/technical data for this oscillator, I would
appreciate getting a scan. I have already received, from a request on
the HP equipment listserv, a copy of an HP10544 schematic.
Also, while performing tests on the unit, I detected fairly strong noise
signals leaking onto my test board. It appears to be coming from pins
5/6 of the HP10544a, which are the EFC control pin and its related
ground. A spectrum analyzer shows the noise at about -30dbm and peaking
around 1.8 mhz. Has anyone seen anything similar with this OCXO?
Everything else looks normal.
Regards,
HOWARD W. ASHCRAFT, Jr.
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Hi Howard,
Please find attached a schematic of the 10544, hope it helps in anyway.
Regards
Gerald
----- Original Message -----
From: "Howard W. Ashcraft" hashcraft@hansonbridgett.com
To: time-nuts@febo.com
Sent: Saturday, February 03, 2007 10:20 AM
Subject: [time-nuts] HP10544a Technical Info needed
I am constructing a GPS disciplined OCXO using an HP10544a. If someone
has a copy of the HP manual/technical data for this oscillator, I would
appreciate getting a scan. I have already received, from a request on
the HP equipment listserv, a copy of an HP10544 schematic.
Also, while performing tests on the unit, I detected fairly strong noise
signals leaking onto my test board. It appears to be coming from pins
5/6 of the HP10544a, which are the EFC control pin and its related
ground. A spectrum analyzer shows the noise at about -30dbm and peaking
around 1.8 mhz. Has anyone seen anything similar with this OCXO?
Everything else looks normal.
Regards,
HOWARD W. ASHCRAFT, Jr.
This communication, including any attachments, is confidential and may be
protected by privilege. If you are not the intended recipient, any use,
dissemination, distribution, or copying of this communication is strictly
prohibited. If you have received this communication in error, please
immediately notify the sender by telephone or email, and permanently
delete all copies, electronic or other, you may have.
To ensure compliance with requirements imposed by the IRS, we inform you
that any tax advice contained in this communication (including any
attachments) was not intended or written to be used, and cannot be used,
for the purpose of (i) avoiding penalties under the Internal Revenue Code
or (ii) promoting, marketing or recommending to another party any
transaction or matter addressed herein.
The foregoing applies even if this notice is embedded in a message that is
forwarded or attached.
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Gerald Molenkamp wrote:
Hi Howard,
Please find attached a schematic of the 10544, hope it helps in anyway.
Regards
Gerald
Gerald
The connection of the 10K oven monitor resistor R12 in the schematic is
incorrect.
In this position only the very small deviations in the oven supply
voltage due to its finite output impedance will be seen as Q4 turns on
and off.
The resistor should surely be connected to the junction of the
darlington (Q4) emitter and the oven heater winding resistor??
The datasheet clearly states that the duty cycle of the oven monitor
varies, as is seen with working 10544As.
Bruce
Hi Howard,
Please find attached a schematic of the 10544, hope it helps in anyway.
Wonder where you got that one ;-)
http://www.leapsecond.com/museum/10544/
I scanned and posted that in 2001; but didn't check the
manual against an actual 10544 oscillator. Should be
close enough for a repair, though.
Hi Bruce,
You are right. I havn't checked my unit against the schematic at all. It is
well secured calibrated and operating in my HP 5342 operating well within
the specifications. The scanned schematic came from Leapsecond a few years
ago, and I have not had to use it as yet. Lets hope it stays that way.
Cheers
Gerald
----- Original Message -----
From: "Dr Bruce Griffiths" bruce.griffiths@xtra.co.nz
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Saturday, February 03, 2007 3:01 PM
Subject: Re: [time-nuts] HP10544a Technical Info needed
Gerald Molenkamp wrote:
Hi Howard,
Please find attached a schematic of the 10544, hope it helps in anyway.
Regards
Gerald
Gerald
The connection of the 10K oven monitor resistor R12 in the schematic is
incorrect.
In this position only the very small deviations in the oven supply
voltage due to its finite output impedance will be seen as Q4 turns on
and off.
The resistor should surely be connected to the junction of the
darlington (Q4) emitter and the oven heater winding resistor??
The datasheet clearly states that the duty cycle of the oven monitor
varies, as is seen with working 10544As.
Bruce
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Gerald
Its about 30 years since I had one of these apart for (sucessful) repair
without the aid of any circuit diagram.
At least one can calculate that the nominal crystal current is about 240
uA rms somewhat less than the 1mA in the 10811 with its SC cut crystal.
Bruce
Gerald Molenkamp wrote:
Hi Bruce,
You are right. I havn't checked my unit against the schematic at all. It is
well secured calibrated and operating in my HP 5342 operating well within
the specifications. The scanned schematic came from Leapsecond a few years
ago, and I have not had to use it as yet. Lets hope it stays that way.
Cheers
Gerald
Gerald Molenkamp wrote:
Hi Bruce,
You are right. I havn't checked my unit against the schematic at all. It is
well secured calibrated and operating in my HP 5342 operating well within
the specifications. The scanned schematic came from Leapsecond a few years
ago, and I have not had to use it as yet. Lets hope it stays that way.
Cheers
Gerald
Gerald
On closer inspection it would appear that to be consistent with the
specified output R8 in the AGC cascode amplifier should be 100 ohms as
in the output cascode amplifier that feeds the emitter follower
otherwise the AGC detector will not develop enough output.
Some modifications to the oscillator circuit were made to improve the
phase noise floor by about 15dB between the early and later versions of
the 10544A.
Thus you will need to know if your oscillator is an early or later
production unit.
I suspect the circuit schematic that Tom scanned is for the early
production unit as the ouput cascode amplifier has an RF voltage gain of
about 13.2x (22.4dB) and a corresponding RF input voltage at the base of
the input transistor of about 76mV rms which is quite low.
Bruce
I have a bad 10544 (received from AST) that I am planning to look into.
No 10 MHz out and very low 12 VDC current.
Has anyone the translation from HP PN to Commercial equiv for the
semiconductors ?
Thanks
Les
Lester B Veenstra
M0YCM K1YCM K1YCM/6Y5
Mail Address:
Lester Veenstra
PSC 45 Box 781
APO AE 09468
Telephones:
Office 940-6456
Office +44-(0)1423-846-385
Home: +44-(0)1943-880-963
UK Cell +44-(0)7716-298-224
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Tom Van Baak (mobile)
Sent: Saturday, February 03, 2007 4:11 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] HP10544a Technical Info needed
Hi Howard,
Please find attached a schematic of the 10544, hope it helps in anyway.
Wonder where you got that one ;-)
http://www.leapsecond.com/museum/10544/
I scanned and posted that in 2001; but didn't check the
manual against an actual 10544 oscillator. Should be
close enough for a repair, though.
/tvb
http://www.LeapSecond.com
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CORRECTION
Judging from the oscillator and oven controller voltage ranges Tom's
scanned circuit is actually for the later production models of the
10544A with the improved phase noise specification. The input signal to
the oscillator buffer cascode was probably somewhat smaller than 76mV
rms in the earlier versions.
Bruce
Lester Veenstra M0YCM wrote:
I have a bad 10544 (received from AST) that I am planning to look into.
No 10 MHz out and very low 12 VDC current.
Has anyone the translation from HP PN to Commercial equiv for the
semiconductors ?
Thanks
Les
Lester B Veenstra
M0YCM K1YCM K1YCM/6Y5
Mail Address:
Lester Veenstra
PSC 45 Box 781
APO AE 09468
Telephones:
Office 940-6456
Office +44-(0)1423-846-385
Home: +44-(0)1943-880-963
UK Cell +44-(0)7716-298-224
Lester
A parts conversion list is available at
http://www.hparchive.com/PARTS/300-hpxref.pdf
The part numbers on the circuit schematic are somewhat abbreviated.
54-215 = 1854-0215 = 2N3904.
53-20 = 1853-0020 = 2N3905?? my guess this should work. but stick a
ferrite bead on the base as this device may oscillate with all 3
terminals AC grounded.
26-59 = 1826-0059 = ?? some low bias current opamp with external
frequency compensation LM208??
3-347 = 1853-0347 = MJE700 PNP power Darlington
4-560 = 1854-0560 = MPSA12 NPN small signal darlington
5-10 = 1853-0010 = 2N2646 unijunction transistor
01-535 = 1901-0535 = Silicon RF detector diode probably not Schottky.
02-033 = 1902-0033 = 1N823 6.2V temperature compensated zener reference
diode.
Bruce