Orion A9 Power Distribution Board Capacitor Repair

Detailed analysis by K7HP of the 81936 A9 Power Distribution Board - Orion 565 and Orion 566 OII

(scroll down for latest advice)

(posts from the Ten-Tec and Orion Reflectors)

April 6, 2007

I came into the hamshack/office to start my day and found my Orion out of commission. The screen was dark and the ALC light was very slightly lit. When I cycled the power switch, I would get the usual double click of relays but the screen would actually turn darker than when it was off and the ALC light was faintly lit. The analog meter light would not come on as well.

Assuming it was a power problem, I took off the bottom panel and inspected the A9 Power Distribution Board. C6 was noticeably stressed with top protruding a bit in a classic electrolytic failure mode. It is a 470 uF 16 volt electrolytic - replaced it with a 470uF 25 volt one I had in the bin. Upon power up, the Orion came up as normal and with the last settings I remember from the previous day.

It occurred to me that the display back light seemed to be getting darker over the last week, but I didn't think anything of it until the hard failure.

It is an easy repair and it took longer to get the cover off than to diagnose and fix the problem. Hope this helps someone…


April 11, 2007

Had exactly the same problem on my orion I, to start with display contrast changed dramatically and then audio started to cut in and out. Switched OFF and then re-booted and radio was completely "DEAD". Fault traced to C6 but C7 & C9 were also changed as these were of a similar type.

Geoff - G0BYH

January 15, 2008

Screen went dark, panel indicators and meter lamps went very dim and receiver went dead. Had bottom cover off, exposing the power distribution board. Phoned T-T fast 'cause it was almost closing time. Paul immediately said he'd ship two caps for the distribution board, C6 & C7. They arrived 4-days later, over the weekend, and my three year old O was running on the fourth day. No charge. Thanks, (St.) Paul.

73, Roy K6XK

June 25, 2008

About 10 months ago, the capacitors on the A9 Power Distribution board failed, and I sent the radio back to the factory to get it fixed. Well, just 10 months later, the same thing happened again. This time, I decided to fix it myself with premium capacitors purchased through Mouser. The fix worked! The 470 uf, 16 Volt, 85 degree C caps, C6, C7 and C9 were replaced with ultra-low ESR 50 Volt, 105 degree C units that fit perfectly in the board.

I have a whole page on my website for anyone interested, including pictures and ordering information for the caps. Hopefully, these will last longer than the first two sets!


Ron N6IE

January 25, 2010

On 1/24/2010 I was on 80 meters and my Orion II "2006 serial number" I notice the receiver cutting in and out and the color display not at the same contrast. I also notice a cracking sound when I went from 80 to 10 meters which you can hear the internal relay switching. Which was not normal but the relay is.

I shut the Orion II down and did a master reset thinking maybe the CPU got confused. After the reset the receiver was still cutting in and out. I shut down the Orion II again and then turned it on again. Now the Orion II was showing all the symptoms like the above post. I removed the PDB a9 and found c6 puffed out.

I wanted a quick fix and did not have the parts. Went to Radio Shack and in the parts draws found 470uf 35 volts 85 degrees. Better then the Ten-Tec caps. Purchase three to replace all three caps c6 c7 c9. As Ron N6IE stated not easy to get out but with patients it can be done. Replaced all three caps and the Orion II is working fine so far. I would replace all three caps to keep things in balance then to just replace one cap. The RS caps were a $1.39 a piece. Part # 272-1030.

So we will find out how these caps will work and update the post if there is a problem.


January 29, 2010

Update - contacted Ten-Tec service department. Tony from service department stated Orion II now comes with upgraded c6, c7, and c9 caps which are 470uf 35v 105 degrees, low ESR. Original caps 470uf 16v 85 degrees not low ESR made by IC. The Radio Shack caps are made by Xicon 470uf 35v 85 degrees "not low ESR" but will work and how long is another question. Will update again when I receive the replacement caps from Ten-Tec. "Update" installed TEN-TEC caps which were "FREE" from TEN-TEC and has been working fine with no problems. You tell me if Yaesu, Kenwood, Icom would send you the parts after the warrantie is up. "Great people at TEN-TEC." "The Best"


January 12, 2011

2 weeks ago I got an Orion1 and when I switched it on , I saw the display was a little dark in the upper left corner and was flickering during transmission. After studying the schematics and some measurements I found the reason. The +5volts on the power distribution board A9 was unstable. During transmission the 5V voltage alternated between 5 and 4,4 volts.

But changing the recommended board-capacitors brought no better results. Then I saw a difference between the board schematic and the circuitry on my A9 board: On my board the upper PNP -transistor was not the original type TO220P NTE 378. Ten Tec had used (how long?) another type BD246C .

Because this one is a TO3P Type and not fittable onto the bord , it was mounted very carefully at the factory via 8cm long wires beside the A9 board on the aluminum case.

I am very sure this outsourced transistor has worked in my Orion since it had left production (Serial Nr. 10C 10584 in 2005).

I ordered the the original NTE 378 from a semiconductor distributor, placed it onto the board and it worked perfectly.


July 19, 2012

For the last several months my Orion (565) has had a screen contrast problem at start-up. Last week I noticed that is was still there but somewhat quicker than it was in the winter months. I thought perhaps I was imagining things so I shut down the rig and rebooted. The screen came up at the correct contrast immediately.

What was going on? The following morning when I turned on the rig I timed the process. Virtually a white screen at start-up and then some contrast at 30 seconds and close to full useable contrast after 2 minutes. Putting all this together suggested something in the circuit was responding to ambient temperature. It was time to dig out the schematics.

The first thought of a culprit was C700 on the logic board (Schematic A7 sheet 15 of 16). C700 is in the contrast line to the LCD and immediately follows the hardware contrast adjustment pot. If this capacitor was leaking or had some temperature stability problem it could be the culprit. I replaced the 4.7 uF @35VDC capacitor but nothing changed.

I felt that my LCD screen was likely good since it was relatively new. So I began to look elsewhere and noticed that the "bottom" of the contrast pot and one end of C700 were tied to VEE.

VEE is generated on the infamous power distribution board and nominally is about -20.5 VDC. So with the rig cool I monitored the VEE at start-up. In a period of 2 minutes it slowly climbed from about -18.5 VDC to -20.1 VDC and then stabilized. This timing matched my Orion screen contrast.

I looked at the power distribution board circuit (schematic A9) and replaced C1 (100 uF @35 VDC) and C3 and 4 (10 uF @50VDC).

After an overnight cool down of the Orion I am happy to announce that this morning there is NO delay in reaching full usable screen contrast at start-up!

73, Rick VE7TK

April 4, 2013

During the WPX contest this past weekend, one of my Orions spontaneously
rebooted on two occasions without me touching anything. There did not
appear to be any power glitch, as everything else in the
shack didn't even flicker. Each Orion has a dedicated TenTec
switching power supply. I had replaced the internal battery
a couple of years ago.

The A-9 Power Distribution Board is bad… classic symptom. You will need to replace either the board, or if you can do basic soldering and have a Radio Shack close by (I know, RS doesn't have the best caps in the world but it will get you back up and running) then you need to replace the 470 uF caps (3 of them). They are rated at 35 volts but if you can find 50 volt caps, all the better. I think they are C6, C7 and C9, the taller of the 9 Caps on that board.

This has nothing to do with the battery and I've had several A9 boards go bad on my 566 and I keep a spare A9 board on hand at all times. If you open the bottom cover the A9 board is right there lookin' at cha.


May 6, 2013

One warning: before taking out the capacitors make a mark on the pcb to indicate polarity…. this because not all capacitors will be mounted with negative to ground.


May 14, 2013

Here are the Mouser part numbers for the Panasonic, Low-ESR, 50WVDC, 108C electrolytic caps I needed to repopulate all the caps on my 565 A9 board:

Mouser Part No. Manufacturer Part No. Description

667-EEU-FR1H221 MFG Part No:EEU-FR1H221 Panasonic Aluminum Electrolytic Capacitors - Leaded 220uf 50WVDC 108C 1 -C2 $0.39ea

667-EEU-FR1H220 MFG Part No:EEU-FR1H220 Panasonic Aluminum Electrolytic Capacitors - Leaded 22uf 50WVDC 108C 3 -C3,C4,C5 $0.09ea

667-EEU-FR1H101 MFG Part No:EEU-FR1H101 Panasonic Aluminum Electrolytic Capacitors - Leaded 100uf 50WVDC 108C 2 -C1,C8 $0.22ea

667-EEU-FR1H471 MFG Part No:EEU-FR1H471 Panasonic Aluminum Electrolytic Capacitors - Leaded 470uf 50WVDC 108C 3 -C6,C7,C9 $0.69ea

TIP(1) - Since I did not really care about the condition of the 'original' caps on the A9 board, I did a 'distructive removal' …. to make the cleaning of the PC board holes easier, and to also prevent overheating the PC board, from trying to remove the old caps (which really are just large heat sinks, when trying to unsolder them from below). This is an old 'US Navy electronics repair depot' trick: To remove the 'dead/old' electrolytic caps, Without heating, Grip the body of the cap with pliers, or fingers, and bend the entire body of the cap over to the PC board. In the Electrolytic caps, like the ones on the A9 board, the internal connection to the leads is made just inside the body of the cap and break off clean…. allowing you to pull the entire capacitor body off of the remaining two mounting leads left behind, still in the PC board. These single solid wire stubs are completely easy to heat, and quicly remove, from the pc board without damaging the PC board from excess heating. Don't worry if the solder hole is clear of left over solder, that gets taken care of in the next TIP.

Tip(2) After TIP(1), Heat one side of each PC board hole, with a pointed soldering iron tip that is centered on the hole. When the solder is melted, use a round (not flat) wooden toothpick, to push through all the melted solder from the opposite side of the hole. The solder does not stick to the wooden toothpick, and the toothpick tapered body displaces all the excess solder from inside the PC board hole. So, the PC hole is left open and solder free, and ready for new components to be inserted.


April 2014

I just replaced all 9 electrolytics on two A9 boards and would offer some advice. When you order your caps, try to obtain caps with the same true lead spacing and don't rely on bending the leads. Use a good soldering iron and solder sucker. I cranked my soldering iron to 800degF because the PCB ground plane sinks a lot of heat. Only use the solder sucker after the caps have been removed. Remove the capacitors by alternately heating each solder pad back and forth and slowly/gently rocking the cap up and out. Don't pull too hard on the caps, especially the small ones, or you will pull the cap body off and leave its leads stuck in the hole. After you remove the caps, use the solder sucker to clear the holes on all pads not connected to the ground plane. They will all clear up easily. I found it impossible to clear the ground plane pad holes so just leave them. Prep the cap leads by cutting the lead that will go through the clear hole significantly longer. Then, just position the cap with the one lead through the hole and the other shorter lead directly in contact with the clogged pad hole. Heat the pad from the opposite side of the board and gently push the cap down to insert the shorter lead. Finish soldering both leads and all caps.

Part numbers for caps I selected, available from Mouser, emphasizing low ESR and high ripple current ratings:

C1, C2 100uF 50V 5mm lead spacing Panasonic EEU-FR1H101B (these use bent leads and it would have been slightly preferable to find a cap with straight leads)

C3, C4, C5 10uF 50V 2.5mm lead spacing Nichicon UTT1H100MDD

C6, C7, C9 470uF 63V 5mm lead spacing Panasonic EEU-FR1J471B

C8 100uF 25V 2.5mm lead spacing Panasonic EEU-FR1E101


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