I'm getting error 6,030,311 which is a failure on the attenuator board (or 2GHz atten?) according to the manual but the attenuators are working fine and output level is accurate over full range. Any ideas what could be the problem?
Even though the accuracy of the attenuators are very repeatable there is a EEPROM that contains the Cal Constants that allow for precision power settings. When the attenuators are replaced so should the EEPROM; EEPROM is matched to the attenuators. Over the years the replacing of the EEPROM has typically not been mandatory due to the repeatability of the mechanical attenuators. Many attenuators have been individually changed without thought to replacing the EEPROM. However, every so often either from drift or just a slight difference, replaced attenuators don’t or no longer meet the expected EEPROM checksum algorithm used during diagnostics or calibration and thus causing a error. This checksum error can be quite small thus not impacting the actual functionality of the unit. Other times there is a perceivable problem. After completing Instrument Level Diagnostics (ILD) and the results is +6,030,nnn then the unit requires repairing to return the unit to full functionality. Of course, if the unit is still meeting the needs of the user for a particular application then just accepting the error and monitoring for any future degradation may be acceptable.
Hi, and thanks for the reply. This unit has mechanical attenuators and there is no facility within the generator to verify their accuracy - these attenuators are relay actuated and provide no intelligent feedback. I understand about the EEPROM and that it contains calibration constants (offsets) for the particular set of attenuators installed. This EEPROM and the attenuators are all the original parts.
Are you suggesting that this EEPROM may have become corrupted and its checksum no longer checks out? This would cause error code 6,030,311?
Do you know if there Is there a default EEPROM available? I recognize this may result in a small calibration error but would be considerably less expensive than replacing the attenuator assy?
Not necessarily suggesting the EEPROM has changed but something within either the diagnostic/calibration algorithm likely has, which both the attenuator and the EEPROM are part of. Past failures indicate that It is more likely that the mechanical attenuator has changed slightly than the EEPROM. As indicated in my initial response, replacing the individual attenuator, which when ordered as the correct replacement part comes with the appropriate EEPROM. If however, the attenuator is ordered by its own P/N then no EEPROM is provided. The majority of these replacements where the EEPROM was not replaced worked just fine without errors. However, there have been cases where the new attenuator and old EEPROM were not compatible and the +6,030,nnn was displayed.
During the production years of the 8664A, the attenuator could be obtained by itself because over the years it had been used in many different products and applications, some of which do not require the use of an EEPROM. The EEPROM was never setup as a standalone replacement part because for this source application; it goes hand in hand with a specific attenuator. The 8664A now is out of support and part availability may be in question.
There really is nothing much on the attenuator board - just 2 attenuator assemblies and the Reverse Power Protection circuitry. The attenuators are wired directly between the RF output circuits of the sig gen and the RF output connector on the front panel (via the RPP detector and a reed relay). The attenuators work fine as the output level is accurate over the full range. There is no facility (within the unit)to measure the accuracy of these attenuators - if they were to drift in value the unit has no way of detecting this by itself. In fact I can unplug these attenuators and the error check results are unchanged. My understanding is that the EEPROM corrects for the accumulated error of the 6 sections of attenuator (3 in each attenuator assy) over the operating frequency range by storing offset values for these.
This error message is flagged almost as soon as the self test is initiated. The self test routine takes several minutes to run so I would suspect it is something quite basic - possibly a check sum error as you suggest? or perhaps the RPP is flagging something is wrong but the instrument does not show RPP has tripped. Perhaps the RPP detector is also used to detect output power from the instrument itself and this is defective?
The instrument also reports hardware failure 6 and calibration failure 2 but I am assuming these are both because of the one error code indicated? There are no other error codes.
I really appreciate your help with this! A replacement attenuator card assy is ~$5,000 and like I said - the attenuators are working fine. No detailed schematics seem to be available so it makes troubleshooting difficult!
With so little circuitry on this board I was somewhat surprised at the number of error codes that point to this assembly. It would be nice if a bit more info was available on each of the error codes.
Here's a little more info... Instrument Level Diagnostics (ILD) yields '+'6,030,311 (with a +). I removed the calibration EEPROM and I get the same error code after power up as I do with it installed - no difference! Monitoring the chip enable for this EEPROM it does not appear that it is read until very close to the end of the power up calibration routine. This is significant because the error message flag is set almost as soon as the power on calibration routine begins so I think it is something very basic that is failing.
I also monitored the RF out (that feeds the attenuator assy) and confirmed that it is muted for the duration of the power on calibration so my suggestion that the RPP detector might be being used to detect sig gen output power is not valid.
My only other idea is that it is perhaps the logic surounding the calibration EEPROM that is faulty.
Pressing the preset button always sets the 'MSG' annunciator which returns Hardware error 6 and calibration error 2. Whatever routine this runs it is not accessing the calibration EEPROM at all - there is no activity on the chip enable.
Even though the accuracy of the attenuators are very repeatable there is a EEPROM that contains the Cal Constants that allow for precision power settings. When the attenuators are replaced so should the EEPROM; EEPROM is matched to the attenuators. Over the years the replacing of the EEPROM has typically not been mandatory due to the repeatability of the mechanical attenuators. Many attenuators have been individually changed without thought to replacing the EEPROM. However, every so often either from drift or just a slight difference, replaced attenuators don’t or no longer meet the expected EEPROM checksum algorithm used during diagnostics or calibration and thus causing a error. This checksum error can be quite small thus not impacting the actual functionality of the unit. Other times there is a perceivable problem. After completing Instrument Level Diagnostics (ILD) and the results is +6,030,nnn then the unit requires repairing to return the unit to full functionality. Of course, if the unit is still meeting the needs of the user for a particular application then just accepting the error and monitoring for any future degradation may be acceptable.
Regards -