Topics

HP141 mainframe with plug-ins


AllanIsaacs
 

Here's a simple question.
I have an HP141T with a spectrum analyser IF module over which is mounted an RF module 8553B.
I want to swap this for the audio module 8556B which I also have.
I managed to pull the pair from the frame with a struggle but how does one separate the modules so I can fit the audio module?
It must be elementary but I don't see how to do it. Once done can the pair just plug back in?
Allan G3PIY


Fred Hall
 

HI Alan.
 
I had this spectrum analyser some time ago and the top and bottom units are connected together with blue Mcmurdo connectors, the bottom unit has the connectors on the top and the upper unit has the connectors on the bottom.
A straight pull up with maybe some leverage should separate the two units.
Also its a long time ago now but I think there is a latching mechanism so look through the cut out sides of the modules and also along the line between the modules at the rear.
I am sorry I cannot quite remember that part.
 
Best Wishes
 
Fred G8IQA
 
 
 
 


On 16 Sep 2020, at 16:20, AllanIsaacs <allan@...> wrote:

Here's a simple question.
I have an HP141T with a spectrum analyser IF module over which is mounted an RF module 8553B.
I want to swap this for the audio module 8556B which I also have.
I managed to pull the pair from the frame with a struggle but how does one separate the modules so I can fit the audio module?
It must be elementary but I don't see how to do it. Once done can the pair just plug back in?
Allan G3PIY


Chris_Suslowicz
 

I should have the user manual somewhere - I'll have a rummage.

Chris. (G8KGS)

HI Alan.
 
I had this spectrum analyser some time ago and the top and bottom units are connected together with blue Mcmurdo connectors, the bottom unit has the connectors on the top and the upper unit has the connectors on the bottom.
A straight pull up with maybe some leverage should separate the two units.
Also its a long time ago now but I think there is a latching mechanism so look through the cut out sides of the modules and also along the line between the modules at the rear.
I am sorry I cannot quite remember that part.
 
Best Wishes
 
Fred G8IQA
 
 
 
 


On 16 Sep 2020, at 16:20, AllanIsaacs <allan@...> wrote:

Here's a simple question.
I have an HP141T with a spectrum analyser IF module over which is mounted an RF module 8553B.
I want to swap this for the audio module 8556B which I also have.
I managed to pull the pair from the frame with a struggle but how does one separate the modules so I can fit the audio module?
It must be elementary but I don't see how to do it. Once done can the pair just plug back in?
Allan G3PIY


AllanIsaacs
 

Thanks Fred and Colin

A hidden button on the left behind the Tuning Stabiliser and on the audio module, just to confuse, the hidden button is on the left.

Both modules have the joining connector. Very tight on the RF unit and loose on the audio unit.

The plan is to look at the Williamson/Moreton Cheyney amplifier

 

Thanks, but I have the manual Chris… just mislaid.

A couple of strata down somewhere…

Allan G3PIY


From: wireless-set-no19@groups.io [mailto:wireless-set-no19@groups.io] On Behalf Of Fred Hall
Sent: 16 September 2020 17:29
To: wireless-set-no19@groups.io
Subject: Re: [wireless-set-no19] HP141 mainframe with plug-ins

 

HI Alan.

 

I had this spectrum analyser some time ago and the top and bottom units are connected together with blue Mcmurdo connectors, the bottom unit has the connectors on the top and the upper unit has the connectors on the bottom.

A straight pull up with maybe some leverage should separate the two units.

Also its a long time ago now but I think there is a latching mechanism so look through the cut out sides of the modules and also along the line between the modules at the rear.

I am sorry I cannot quite remember that part.

 

Best Wishes

 

Fred G8IQA

 

 

 

 


Chris_Suslowicz
 

Allan (G3PIY) wrote:

Here's a simple question.
I have an HP141T with a spectrum analyser IF module over which is mounted an RF module 8553B.
I want to swap this for the audio module 8556B which I also have.
I managed to pull the pair from the frame with a struggle but how does one separate the modules so I can fit the audio module?
It must be elementary but I don't see how to do it. Once done can the pair just plug back in?
OK, I found the Model 8555A RF section instructions:

2.21 To separate the RF/IF sections from Display section and to separate the RF section from the IF section proceed as follows:

a. Push front panel latch in direction of the arrow until it releases. (Note: this is the black plastic rectangle at the left hand top of the IF section, on the joint between that and the RF section.)

b. Firmly grasp the middle of the latch flange and pull the RF/IF sections straight out.

c. Unlock the latch on each side of the RF section and exert an upward pulling force on front edge of RF section.

d. When the two sections separate at the front, raise RF section two or three inches and slide metal tab at rear of IF section out of the slot with which it is engaged.

Best regards,

Chris. (G8KGS)


Colin_Tuckley
 

On 16/09/2020 16:20, Allan Isaacs wrote:

I managed to pull the pair from the frame with a struggle but how does
one separate the modules so I can fit the audio module?
It must be elementary but I don't see how to do it. Once done can the
pair just plug back in?
Once you have the pair out of the frame there is a release latch on the
left hand side of the top (8553B) module. It's a black plastic recessed
button near the front (just behind the "Tuning Stabilizer" control).
Push the button and lift the front of the top unit to release it and
then move it backwards to disengage the hook at the back.

73 Colin

--
Colin Tuckley | +44(0)1223 830814 | PGP/GnuPG Key Id
G8TMV | +44(0)7799 143369 | 0xFA0C410738C9D903


AllanIsaacs
 

The hidden button on the RF unit is on the LEFT and the hidden button on the
audio unit was on the RIGHT.
I confused myself. Quite easy to do of late.
Allan G3PIY

-----Original Message-----
From: wireless-set-no19@groups.io [mailto:wireless-set-no19@groups.io] On
Behalf Of Colin_Tuckley
Sent: 16 September 2020 18:03
To: wireless-set-no19@groups.io; Allan Isaacs
Subject: Re: [wireless-set-no19] HP141 mainframe with plug-ins

On 16/09/2020 16:20, Allan Isaacs wrote:

I managed to pull the pair from the frame with a struggle but how does
one separate the modules so I can fit the audio module?
It must be elementary but I don't see how to do it. Once done can the
pair just plug back in?
Once you have the pair out of the frame there is a release latch on the
left hand side of the top (8553B) module. It's a black plastic recessed
button near the front (just behind the "Tuning Stabilizer" control).
Push the button and lift the front of the top unit to release it and
then move it backwards to disengage the hook at the back.

73 Colin

--
Colin Tuckley | +44(0)1223 830814 | PGP/GnuPG Key Id
G8TMV | +44(0)7799 143369 | 0xFA0C410738C9D903


Mike
 

Allan,

I also have a 141T with all 3 RF modules but no AF one.  You might also consider some PC software to analyse the audio.  There seems to be plenty around for free download which would at least show the spectral response and also (probably!) the THD figures.

 

My 141T is now redundant as I have recently acquired an 8593E with the 26.5GHz option...  Wow! J

 

73, Mike,

Mike Stevens,

G8CUL/M0CUL/F4VRB.

 

 

The hidden button on the RF unit is on the LEFT and the hidden button on the audio unit was on the RIGHT.

I confused myself. Quite easy to do of late.

Allan G3PIY