[time-nuts] HP5334A Option 010 replacement connector J8
Hello list, same guy who direct-wired a STP2390C into a HP5334A earlier this year back here again. As a christmas holidays nano-project I made a little PCB to have a nice plug-in module instead of a snake nest. Today the boards arrived from the factory, and it was a lesson in "dont try to design a PCB when 2 little ones are running around you". Swapped two pins. Minor other things. But nothing that a drill press, scalpel and a piece of enameled wire can`t fix. Also users outside germany might want to use the permanent powered +30V rail instead of the +15V I settled for and so far cannot decide if I also change. Besides the STP2390C, it needs to be populated with a 7812 voltage regulator and some chicken food, and with a little cable run a Trimpot on the "OSC ADJ" opening can be connected too. Space for add-ons provided, mine has 1K in series from osc output to PCB output. Details will follow soon, I will post a description with updated eagle files on my website. Now I have some leftovers that I would like to offer time-semi-nuts that want such a OCXO in their beautiful 5334A. €3 for a unmodified buggy board, €5 for a board with the "subtractive corrections", say drill and cut sound about okay? Of course with additional shipping fee from germany that I have to figure out, bare PCB, no other parts. Best regards, Hendrik ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP5334A Option 010 replacement connector J8
I was the Project Manager for the 5334B. The A version (unlike the B version) has a very weak power supply due to insufficient capacitors and/or transformer. I can't remember now after 25 years. When you power it up with a cold 10544 or 10811, the oven circuit looks like a 47 ohm resistor. The 5334A can only muster 12V into this load. This is way below the 20V minimum operating voltage. However, the 10811 turns out to work well enough on 12V to get the oven warmed up. Once the oven current cuts back, the voltage will zoom up to something like 24V, being unregulated. This passes for "normal" in the 5334A design. So do not be alarmed by this behavior if you are trying to do a sanity check. Rick Karlquist N6RK On 5/21/2014 1:18 PM, Hendrik Dietrich wrote: Dear group, as I just yesterdays implanted a non-original OCXO (C-MAC STP2390C) into a recently ebayed counter, I wanted to share my experience: Swapping C8 to C100 position as per 5334B Service Manual (the B) is fine. J8, the connector for Option 010, is not in the 10811 layout as in the B. As I cannot find a A service manual, I had to poke and trace. This table will give you the pinout of the connector J8, with the lowest row representing the pins that are closer to the front, seen from component side top and the left column closer to the right edge of the PCB: OFF State +30V I +30V GNDI GND I I +15V I +15V I 10 MHz out ON State +29V I +29V GNDI GND I -5V I -5V +15V I +15V I 10 MHz out A 10 turn pot was mounted on the hole on the backside of the unit, connected to the EFC input of the Osc. as a voltage divider of course. All wires are twisted pairs (or twisted triple talking about the EFC.) even the 10 MHz is not a coax - yet. Having the rig open, I discovered burnt resistors at the 50 Ohm Termination of Channel A (only used B terminated so far), where the previous owner even stacked new resistors right on top of the original ones. (both pairs burned). A 619 Ohm Resistor in the ARM Path was also burned but Diodes OK, so I replaced it with a 620 Ohm Resistor, as expected without adverse effects. Counter and OCXO cost me about the price of a single 10811. Greetings Hendrik ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] HP5334A Option 010 replacement connector J8
Dear group, as I just yesterdays implanted a non-original OCXO (C-MAC STP2390C) into a recently ebayed counter, I wanted to share my experience: Swapping C8 to C100 position as per 5334B Service Manual (the B) is fine. J8, the connector for Option 010, is not in the 10811 layout as in the B. As I cannot find a A service manual, I had to poke and trace. This table will give you the pinout of the connector J8, with the lowest row representing the pins that are closer to the front, seen from component side top and the left column closer to the right edge of the PCB: OFF State +30V I +30V GNDI GND I I +15V I +15V I 10 MHz out ON State +29V I +29V GNDI GND I -5V I -5V +15V I +15V I 10 MHz out A 10 turn pot was mounted on the hole on the backside of the unit, connected to the EFC input of the Osc. as a voltage divider of course. All wires are twisted pairs (or twisted triple talking about the EFC.) even the 10 MHz is not a coax - yet. Having the rig open, I discovered burnt resistors at the 50 Ohm Termination of Channel A (only used B terminated so far), where the previous owner even stacked new resistors right on top of the original ones. (both pairs burned). A 619 Ohm Resistor in the ARM Path was also burned but Diodes OK, so I replaced it with a 620 Ohm Resistor, as expected without adverse effects. Counter and OCXO cost me about the price of a single 10811. Greetings Hendrik ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
