help: HP GCD 1800A

[jtung]

I've just been "gifted" with a HP GCD-1800A along with a DOS ChemStation (without monitor or keyboard; looks like a 25/50 MHz processor). It was last operational in 2003 and its former operators have left the area.

A web search makes it look like it might have been a predecessor to the 5890 series.

I haven't tried the chemstation yet, but its inclusion and a taped-up procedures that shows "m/z=450" makes me think its a GC-MSD. Unfortunately, the last time I used one was 20 years ago and the printout format looks ... um, consistent with something from 20 years go.

So, my questions:

1) Did the 1800A have a non-mass spec detector configuration? The front of my instrument's oven say "electron ionization detector".

2) Anybody with experience with this instrument? Is it worthy of use with high schoolers? Water analysis? QA/QC? I suppose its a function of the operator skill level, but what's a reasonable expectation?

Thanks in advance for any help.

[Ron]

This was a rather odd product that never caught on. It was a lower cost version of their 5971 mass spectrometer, but basic mass spectrometer function such as tuning were removed. It is a GC detector that does provide some mass information, but since it only had signal optimization and not tuning it could not be used for applications where tune criteria had to be met, such as environmental analysis. In addition, the mass patterns were not always a good match to library mass spectra, since tuning adjusts mass pattern to match standard conditions.

What you have is an interesting piece of instrumentation history, but I personally would not put too much time and effort into this.

[fomalhaut]

I too am making two old GCD 1800 systems (1996 vintage) hang on for now and it's a real job what with WIN95 and old PC and HP hardware.

Someone mentioned in an archive post that they had obtained the "HP service password" for the GCD. If anyone knows it or how to obtain it let me know.

In addition, it appears all macros are "protected" and unreadable. Can anyone give suggestions for making them readable and/or editable?

[LCbob]

username is ceuser
password is paloalto

There were two versions of software, pre and post year 2000. If you have a copy of the pre 2000 let me know as I have been hunting around for this for ages.

[EntomoChem]

Hello everyone,
I am supposed to receive a HP G1800A GCD tomorrow, included is:
HP1800A:
GCD Plus ChemStation ver A.01.00 - NO PASSWORD Installed
(Software on Computer, No disc included)
Manuals:
(2)HP G1800A GCD Users Guide
GCD Installation Manual
GCD Quick Reference Guide
HP Vectra XM User's Guide
HP Network Administrators Guide
HP LaserJet 4Plus Getting Started guide

I was thinking of starting a new "Topic" for those of us working with this dinosaur, so that maybe we could help each other out.

[fomalhaut]

A new topic sounds like a good idea but I fear it would attract little interest. The two GCD machines we have are powered up but are only used when all else is unavailable and therefore they are used sparingly. No one is in charge of managing these machines and they can quickly fall into moribund status. My own "expertise" is slowly fading as I seldom interact with them anymore unless a crisis occurs. I hope your experience with the GCD is at least interesting and I will be glad to help if needed. Cheers.

[EntomoChem]

Okay, So I just got my GCD and began pump down last night, this morning I came in expecting the pump down to be complete. However, I saw this: 66mTorr Diffusion Pump is on but cold. I have cycled the MS off and on to reset the DP circuitry, but can not get the DP to go hot. Any help would be much appretiated.

Thanks
Mark

[EntomoChem]

I'm trying to get my boss to let me open the GC oven to see the analyzer door is pressed in in order to create vacuum conditions, and to inspect the column, does this seem like something to check?

[EntomoChem]

I'm thinking it is the DP too hot/too cold sensor. Any Ideas? The DP is blowing hot air so I assume that the heater is working and the sensor is not!

thanks
Mark

[fomalhaut]

I am reviewing my notes and will get back with you soon on this subject.

I don't understand your statement about opening the GC oven to check the analyzer door. Not sure what you are referring to.

[EntomoChem]

From the Agilent website concerning too cold error message on a 5971/5972A MSD:

NOTE: During initial pump down, it maybe necessary to push down lightly on the top of
the analyzer until the vacuum is able to pull the analyzer top plate down and makes a
seal on the Analyzer Manifold O-ring.

I'm thinking it is probably the DP sensor? It is most definitely the too cold sensor as it is missing the small piece of metal that deforms under temp differences, I found this place which seems to be one of the only places that has a decent selection of parts for GCD.:

http://www.gentechscientific.com/hp-597 ... ld-switch/

I'll let you know once the part comes in and I replace it!

Thanks for any and all the time answering my post and hopefully you didn't spend too much time looking thru your notes!

Thanks,
Mark

[fomalhaut]

First: it is possible that the diff pump heater is faulty; verify by removing the diff pump shroud assy; reset system and restart pumpdown; when mechanical pump brings vacuum down to about 100mTorr, diff pump heater should start; feel the bottom of the diff pump to see if it is heating up; it should get warm to the touch within about 20 minutes; if no heating detected shut down and unplug diff pump; remove diff pump plug to chassis and check for continuity of the heater cartridge

Second: Msg of "66 mTorr" means mechanical rough pump is doing its job and there are no major leaks preventing vacuum system from starting; lower vacuum levels can only be acheived with diff pump assistance

Third: for your statement "DP is blowing hot air", you are probably feeling output from the chassis fan behind the diff pump which is designed to help cool the upper part of the pump; this is normal but doesn't mean the diff pump is working(heating)

Fourth: the diff pump has two sensors mounted; the lower one senses the initial heat from the main diff pump heater at the bottom of the pump; upper sensor senses when top of diff pump overheats and it will shut down the diff pump heater to prevent damage to the pump

Lower sensor: normally open switch; when it senses heater is working(about 175 deg C), switch closes and allows the MS electronics to come on; if no heat detected, lower sensor switch will not close and system will not come up any further; if switch is faulty, it may be stuck closed or open

Upper sensor: normally closed switch; opens upon excessive heat detected in the upper pump(about 185 degC); prevents damage to pump and analyzer; if switch opens entire system will shut down

You should look at the lower switch first and the heater cartridge itself.

I have ordered these switches from Allied Electronics in the past for a lot less than other sources, approx $50 each.

I hope this helps.

[EntomoChem]

Very Helpful thank you. All the same conclusions I came to at the end of the day. Nice to know I'm on the right track.

Kindly,
Mark

[EntomoChem]

hi my friend,
so i replaced the too cold sensor. ( my boss did as i was out of town), however now I'm seeing an error 512, concerning high voltage, I've just ordered the Too Hot sensor and i'm hoping that is causing the problem as the diff pump is definitely getting too hot!! any thought's or ideas?

thanks in advance!

mark

[fomalhaut]

I refer to the two diff pump sensors as lower and upper so I am not sure which one u replaced. What is the full text of the error msg?