Sorry, it wasn't clear that you had already tried a generic service center and they had surmised it was something in the main circuits. At least you've past step one, determining whether its a simple fix or not (apparently not).
Pioneer hasn't sold a recorder in USA since the model 640 of 2006, and their support website basically blows off any inquiry regarding service for Pioneer recorders in the Los Angeles area with an advisory to "call them at (800) 421-1404 to discuss your options." My guess would be the official USA options for a Canadian 450 in Los Angeles would be nil: your best bet would be to tell them you have a 640, and try to get the address of a local service tech that handles that model. Then you can bring your 450 there and by dealing directly I'm sure they can fix it. The 450 came one year after the 640, other than the video encoder I don't think there was any substantial internal change and most control circuits should be similar. The similar Sony RDR-HX780 was a Canada exclusive as well, so Sony USA wouldn't be any use to you at all.
You CAN temporarily swap the HDD from your dead 450 into your working 650, burn the contents to DVD, then return the original 650 HDD back into the 650. It won't erase or re-initialize either HDD as long as you have the necessary Service Remote and Service Disc, and follow official swap instructions. Pioneer long since stopped selling these service tools, but the Sony J-609-0203-A version of the remote is still available as a generic knock-off for roughly $25 from web dealers like this
. For the service disc, you need to drop an email request to Hakan, the admin for the user-based pioneerfaq repair/upgrade website. The email address is supportATpioneerfaqDOTinfo. Ask for assistance in locating a download of the "Pioneer GGV1321 Type 2 Data I.D. Disc." After finding the disc, be sure to make a small donation to the pioneerfaq website using their provided PayPal link: the site is a lfesaver for Pioneer recorder owners and run by users for users, the small donations they get are critical to keep the site running. After downloading and burning a Service DVD, the following pioneerfaq instructions will allow swapping the HDD between your 450 and 650 without having to erase it:
1. remove the HDD from your 650 and set it aside.
2. remove the HDD from your 450 and install it in your 650.
3. Power up the 650 and it will flash HDD ERR or CPRM Err on the front panel as well as your TV screen.This means you need to reset the CPRM code on the HDD from the current 450 code to the 650 code. Look on the 650 rear panel for a secondary small white label with a nine-digit code number, its located near the fan or the AC socket. Write down the nine digits.
4. On your service remote, press ESC and then STEREO. Service mode will activate and a service display will appear on your TV. Enter the nine-digit number you wrote down using the service remote number keys, then press STOP.
5. Press ESC and STEREO again, enter the nine digit number again, and press SEARCH.
6. The recorder will ask for the ID Data Service Disc. Load the service disc and close the tray. After a moment, your TV should display "Rom Write OK!"
7. Press CLEAR on the service remote. The recorder will exit service mode. Remove the service disc BUT DO NOT CLOSE THE TRAY. Turn the recorder off, the tray will close itself. Wait a moment, and turn power back on. Your 650 should work normally with no ERR alerts from this point on. When you press the HDD Nav button on the 650 remote, it should display the contents of the 450 drive normally and let you burn DVDs from it.
(If your TV displays Rom Write NG! instead of Rom Write OK! in step 6, don't panic. Sometimes the recorder trips over itself, or you enter the nine digits in the wrong order, and have to start the CPRM process over again. It nearly always "takes" the second time around.)
A couple of clarification points that aren't always obvious from reading the pioneerfaq instructions:
During steps 4 and 5, you need to enter the CPRM number *twice.* A lot of people don't realize this and get stuck. You hit ESC+STER, enter the number, press STOP, then ESC+STER a second time, then enter the number a second time, then press SEARCH (instead of STOP).
In step 7, be careful NOT TO CLOSE THE DISC TRAY after removing the service disc. Just take out the disc and turn off the power, the 650 will close the tray by itself. If you close the tray by hand before turning off the power, the entire CPRM process can get corrupted resulting in HDD Err, meaning you have to start the whole thing over.
This is much more complicated to describe in words than it is to actually do, it only takes about 2 minutes to reprogram the 450 HDD to work in the 650. After you finish dubbing all the videos off the 450 HDD, you have several choices how to proceed.
You can leave the 450 HDD in the 650 and just use the recorder as if nothing had changed.
Or, you could put back the original 650 HDD (which I believe was larger at 250GB vs the 450 HDD being 160GB). Returning the original 650 HDD does not involve using the service tools, when you power up after the swap the 650 should just recognize its own original HDD as if it had never been removed.
Regarding the 450 HDD, remember it has now been reprogrammed to be recognized by the 650 and not the 450. If you don't want to repair the 450, or find you can't get it repaired in the USA, set aside the 450 HDD as a spare for your 650. At any time in the future, you can instantly swap the 450 HDD back into the 650 if you run out of HDD space or the 650 HDD dies. For the time being, you can put the 450 HDD back in the 450 and set the whole recorder aside as a spare parts machine: you can use the 450 burner and HDD as spares for your 650 should the need arise.
You won't be able to use the 450 HDD again in the 450 until you get it repaired, because you need it to turn on so you can use the Service Remote and Disc to program the HDD back to the 450 CPRM code (the number on the little white back panel label). Since your 450 won't currently turn on anyway, the Pioneer service center would naturally just reprogram the HDD after they fix the power issue (if indeed you can locate a Pioneer service center).
BTW, if you do opt to buy your own service remote and download the service disc, DO NOT mention it to the Pioneer hotline or service center: play dumb, and let them fix it without knowing you touched it. This way they can't possibly lecture you about self-repair being a no-no.