Onkyo TX-2500 MK II - PCB labels don't match SM

[Ray66]

I'm currently working on an Onkyo TX-2500 MKII receiver. I noticed a disconnect in PCB naming between the service manuals I downloaded from HiFiEngine and the actual unit I'm working on. For example, the label on the POWER AMPLI. PC BOARD in my unit is NCDA-472 while the manual lists it as NADA-472. Apparently I have a different version but I didn't notice much difference (until today). I was tracing back the part of the circuit controlling the Stereo, Tuned and Locked lights and see that R905-R915 are shown on the schematic to be on Power Supply Board NAPS-473 (mine is NCPS-473), but these are actually on the the power amp board mentioned above. Does anyone know if there's a revised manual floating around out there that matches my unit?

 

[aldena007]

It is not likely that a "revised manual" exist. If you are lucky you might locate a service manual plus documentation of all post production changes the OEM published. This is why the general consensus of the Audiokarma community recommends [strongly] you document the configuration and layout of the unit under repair as the official version before you make changes. This of course applies if you are confident that nobody has been in the unit first and made changes. The original OEM service manual is a general guide at best.

Service Manuals were produced for certified service centers for each manufacturer prior to production of each relative product. They were distributed to their service centers prior to the products hitting the market and are relevant only to the initial production products. After the products/units were distributed the bugs/problem reports began to come back to the OEM's. Bug fixes then were made to the production of the units and some type of service note/upgrade kit/remediation procedure was distributed to the respective service centers. Often the needed remediation involved components and/or circuit boards. When these "repairs" were done the original service manual were to be updated locally with the documentation supplied for any given field service action. In general factory service manuals were not widely distributed beyond official service centers and they often were expensive to purchase. Most of the follow on documentation is rarely available.

 

[kwayde]

You can post what problems you're trying to work out to see if anybody has any positive input.

 

[avionic]

while the manual lists it as NADA-472.

Most likely one of many typo's in the manual.

 

[krautmaster]

The Service Manual I used for my Onkyo M508 has three different sets of schematics included, one for the UD 120 V/60hz models, one for UG 220V/50hz, and the one I used for my switchable UW 120/220V 50/60hz model. The only difference appears to be on the power supply portion of the board.
The Service Manual for my Onkyo TX-4500MKII has sections for the USA model and the "Universal" model (I assume switchable voltage models). There MAY be a manual for the 2500 MKII out there that shows the differences between the voltage variants, but I haven't found it yet (I'll keep looking because I'm bored !)

 

[KingBubba]

The difference you describe is a very common issue. Stick with what is actually mounted on the physical board as you reference your replacement components.

 

[Ray66]

Thanks to all for the input so far. Here's a little more info as an FYI for anyone working on one of these receivers.

There are two service manuals found on HiFiEngine:
hfe_onkyo_tx-2500_mkii_service.pdf
hfe_onkyo_tx-2500_mkii_service_alt_scan.pdf

The first pdf version has 14 pages but the last page number of the document is pg17 (pg 13-14 missing). However, it has corrections made in handwriting to alignment procedure on pg6 as well as various notes handwritten on the schematic. The second (alt_scan) version is 17 pages long and appears to be complete. It was also scanned in color so the PCB layout images have the traces shown. I’ve imported the parts list from the alt_scan version into an Excel file.

As mentioned in the initial post, the board labels on the unit I’m working on differ from what is listed in the service manuals.

PCB SM Label My Unit
AM/FM TUNER & EQUALIZER NARFE-470 NCRFE-470
POWER AMPLI. PC BOARD NADA-472 NCDA-472
PREAMPLI. PC BOARD NAAF-471 NCAF-471
RECTIFIER PC BOARD NAPS-473 NCPS-473

For the most part the boards appear to be similar, however as noted earlier I did notice a discrepancy related to the stereo/tuned/locked lamp section of the circuit. I’ll post the parts list with differences noted once I’m done.

 

[Ray66]

Here's the aforementioned Excel file containing the parts list scanned from hfe_onkyo_tx-2500_mkii_service_alt_scan.pdf. I've noted any discrepancies with the unit I'm working on. There was one transistor that was different than what was listed in the SM, but I know for sure someone else has worked on this so it's possible it was changed. It appears that we can't attach .XLXS files so it was saved as a comma delimited (CSV) file. Hope this is useful.

 

[Mico]

I worked on all the receivers from that series but never relied too much on the SM. Less mistakes than with some other manufacturer`s documentation but still not having all the changes which came during the unit`s production span.

 

[Ray66]

I worked on all the receivers from that series but never relied too much on the SM. Less mistakes than with some other manufacturer`s documentation but still not having all the changes which came during the unit`s production span.

Thanks for the reply. I've worked on several different brands of vintage receiver/amps but this was the first Onkyo for me. Ironic that the unit with the nicest PCB markings (components identified on both frontside and solder side) has the worst SM.