My preamp died today!

halo71

Well crap. I went to turn on the stereo for some tunes on my day off. I hear a click as usual then nothing. No power to the pre. It is a Onkyo P-301. Been a great unit for many years, now its dead. I pulled the cover and don't see a single fuse anywhere.

Anyone got any experience with this unit? I don't have the cash for a new preamp right now, unless I sell or trade a guitar or two. I have an old Pioneer AVR with preouts I could use as a pre I guess. May be a short term solution. :frown:

Sucks being broke! lol

zingo

Here is the download of the manual and schematics. I looked, but couldn't see a fuse either. Do you have DMM you can test with?

http://www.eserviceinfo.com/downloadsm/49471/Onkyo_P301.html

halo71

Thanks but no I have no way of testing it. I can get a meter, but have no clue what to test.

The Pioneer AVR I have I was going to use as a pre seems to be not working either. I REALLY hate to go back to a dedicated Onkyo AVR with no preout. :mad: Guess I will have to for the time being.

TECHNOKID

zingo wrote: »

Here is the download of the manual and schematics. I looked, but couldn't see a fuse either. Do you have DMM you can test with?

http://www.eserviceinfo.com/downloadsm/49471/Onkyo_P301.html

halo71 wrote: »

Thanks but no I have no way of testing it. I can get a meter, but have no clue what to test.

The Pioneer AVR I have I was going to use as a pre seems to be not working either. I REALLY hate to go back to a dedicated Onkyo AVR with no preout. :mad: Guess I will have to for the time being.

I am not sure is the download zingo has provided you is the same as the one I was looking at (Onkyo P-301) but if so, I would first check RL 901 (Relay), if you can open it up and clean the contact with a burnisher and try it again. If it works, try get an aftermarket relay or keep it going as long as it last. Then, if this is not the problem, I enlarged the schematic diagram (p. 13) in the power supply area 400% and noticed that there is a fuse hiden in the primary of the transformator. This can be tricky to access as the fuse is often covered within the Xfo mica/paper proptection. If this fuse is blowned, I would suggest you bypass it and install an in line fuse in lieu. However, as usaul such fuse doesn't have any rating (racket to get people to replace the Xfo :mad: ). Try get a value from the company or use imagination for replacement value (some close to typical value in other preamp).

Good luck!
TK

disneyjoe7

I see the fuse you're talking about on the primary side of transformer, but since I feel it's alive all the time if the transformer is warm I would assume good. Now saying that the RL 901 relay looks as it turns Off or On the switched outlets only. If transformer is working I would expect a bad transistor in the power supply, and or a bad solder joint.

Halo71,
BTW don't like you stated 2 pieces of equipment aren't working, did you have a storm or something?

halo71

The transformer was warm after I unhooked everything and pulled the cover. I didn't see or smell anything burnt. I need to get a meter I guess. The standby light does not come on either. When I turned it on this morning, it did it's normal click then no power.

The Pioneer AVR has been in a closet unused for several years. It powers up but no sound. Through its speaker outputs or running my M504 on the preouts.

Tony M

I have three and sold a fourth Onkyo amps that when powered on, only click once. No power afterwards because those relays need to double click or at least send the power to another so you get that double click sound.

Man I need to get these things fixed!!!:mad:

halo71

This one won't even click at all. :frown: I always liked this pre but its not gonna be worth putting in the shop to be fixed.

disneyjoe7

If you like to get into get a meter and start checking voltages, I think your 5.1v is down.

halo71

Thanks for all the help and advice. Digging through my closet today, finding 2 guitar necks I forgot I had, I found a Sony SDP-E800. Haven't used it in years. Its a DD processor that is now serving preamp duty for the time being. Actually I think it sounds better than the Onkyo P301.

I may hook up a few more power amps I having laying around and get back into 5.1. The wife has actually been after me to hook surround up again for a while.

And actually now that the wife found a job again. Maybe sometime in the near future I will be able to get a cheap tube preamp for 2 channel. :cool: If anyone has a pre to trade, I have several electric guitars that are in the $350 to $500 range. But at least I have tunes again! :biggrin: Just glad my M504 is still kicking.

cnh

Good news! I've been reading this thread with interest and glad that you've got a workable solution. Pre-s aren't cheap these days...I, know, I've been trying to pick up a second one and don't want to spend a small fortune doing it.

My current pre is also an Integra/Onkyo that has been acting up--so I tabled it. But this thread inspired me to take it out of mothballs and DeOxit the thing to death after looking inside and seeing that things looked OK--to me. So far so good. Fingers crossed.

And good luck on the hunt! If I see anything I'll send it your way!

cnh

halo71

Time to hit the thrift store in Athens and Augusta I guess. lol

TECHNOKID

disneyjoe7 wrote: »

I see the fuse you're talking about on the primary side of transformer, but since I feel it's alive all the time if the transformer is warm I would assume good. Now saying that the RL 901 relay looks as it turns Off or On the switched outlets only. If transformer is working I would expect a bad transistor in the power supply, and or a bad solder joint.

Halo71,
BTW don't like you stated 2 pieces of equipment aren't working, did you have a storm or something?

Agreed on potential bad Q and/or cold solder joint(s).

tony millard wrote: »

I have three and sold a fourth Onkyo amps that when powered on, only click once. No power afterwards because those relays need to double click or at least send the power to another so you get that double click sound.

Man I need to get these things fixed!!!:mad:

Then that would mean the coil of the first relay would do its job to move the wiper to mate contacts but it seems it doesn't actually make contact (could be due to burned/deteriorated contact on the wiper and junction) thus not feeding the second relay coil which is not activated thus the reason for not hearing the second relay click therefore leaving the relay in the open position?

As DJ points out, potential cold solder joints are not out of the picture either. Some to remember with relays, the fact that you hear the click simply means the wiper is moved into position for the closing state however it does not mean that the closing state/path is successfull. What is to keep in mind is that the coil is electric function but the remainder of the relay is mechanical. Contacts sparks every time a relay is used (be on or off) and this over time deteriorates the contact to the point that it eventually no longer provides the path it was designed for.

IMHO, an easy way to check a relay is while the equipment is disconnected, use a small battery (IE: 9 volts for most of our gear should suffice) to manually trigger the coil. You should hear the coil clicking thus moving the wiper in place in order to create the desired circuit path. Now that you know your coil is working, you want to keep the relay energised so can now verify that the path is complete using your (multi)meter. If you read an open, then you might want to consider inspecting the inside of the relay for mechaninal malfunction or replace it if sealed. On the other hand, if the relay reads a short on the (multi)meter while energised, you can be assured your problem is not the realy and therefore you should proceed checking the other components in that path (runs, solder, resistors, diodes, caps, Qs etc...).

halo71

^I hear no clicks at all now.

I might pull the cover this weekend and check for cold solder joints. Hope to borrow a meter from work too.

TECHNOKID

halo71 wrote: »

^I hear no clicks at all now.

I might pull the cover this weekend and check for cold solder joints. Hope to borrow a meter from work too.

A multimeter versus a meter would be of better use (unless you met multimeter?) as it will allow you to not only check continuity but will also allow you to check for voltages and potentially current.

DJ has mentined that RL901 would only control the onboard power outlet but I am not convinced of that since there is a junction point out of the relay wiper that connects both the wiper and the outlets.

Yesterday, while I was focusing on the relay, I did not notice the connection below C901 which looks like a run/short between the both sides of the relay which would bypass the relay however, there is a number (103) accompanied with voltage value (125 volts). Could this be a component of some sort rather than just a short run (otherwise, it would defeat the purpose of the relay for both the Xfo and power outlets?

Now, you are saying you no longer hear the relay clicking, does the Xfo still warm or is it now cold? If cold, it might have been a component that was slowly dying. If I were you, I would first use the multimeter to trace the voltage up to that Xfo primary. If there is no voltage (roughly 125 volt AC) then you should focus in that area. If the voltage is there, go across the Xfo at the secondary and check for your voltages. If voltages are at the secondaries then start checking the DC Power Supply Section components (resistors, diodes, Qs etc...) ohmique values.

halo71

^ Thanks! I will get a multi meter this weekend from work.