Spectracom 8195 "Ageless Oscillator" - Page 1
Forum section: electronics / repair

author: K1FPV
author_rank: Contributor
timestamp: August 30, 2016, 10:15:54 pm
content: Has anyone had any success repairing and or acquired the service info. (schematic & Repair info.) on the Spectracon 8195 "Ageless Oscillator"?BillK1FPV

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: August 31, 2016, 05:19:30 pm
content: Did you by chance have a phone conversation, or exchange of email with Spectracom Support???They have been quite helpful in the past. If they do not have the schematic, and board prints though, I guess you are on your own to find it.

author: edpalmer42
author_rank: Super Contributor
timestamp: August 31, 2016, 08:20:09 pm
content: I haven't repaired one, but I've got one that was working last time I looked at it. I wasn't very impressed with its performance, but it appeared to be meeting its specs. What problems are you seeing? Maybe we can at least compare symptoms.Ed

author: K1FPV
author_rank: Contributor
timestamp: September 01, 2016, 12:21:58 pm
content: OK, thanks guys for the reply. Yes, I've contacted them and communicated via email as well as the telephone. They said that they no longer support it! It is also proprietary and as such will not release service information. I've exchanged a couple emails as well as speaking to a tech on the phone.I think I've solved the problem as I picked up another, later model and compared the waveforms & voltages and have come to the decision that the Motorola GPS receiver module did not have any output. I found a new/old stock receiver board on eBay for $15.00 so I'll let you know how I make out when I get the new receiver.BillK1FPV

author: edpalmer42
author_rank: Super Contributor
timestamp: September 01, 2016, 04:39:14 pm
content: I believe the GPS receive is a Motorola Oncore M12. It should be easy to remove it and bench test it. There's lots of info out there on that model.Ed

author: K1FPV
author_rank: Contributor
timestamp: September 03, 2016, 12:35:26 am
content: Thanks Ed on the reply. Yes, I know that it has the Motorola receiver. It is working as I get the 1 PPS out. I keep getting a major and minor alarm, even after a 24 hour warmup. It is usually a CPU error message. I'm tearing my hair out....both of them!Bill

author: edpalmer42
author_rank: Super Contributor
timestamp: September 03, 2016, 03:12:48 am
content: Quote from: K1FPV on September 03, 2016, 12:35:26 amDo you have another reference to compare either the 1 PPS or the 10 MHz to? Maybe the CPU can't talk to the GPS, but other than that, it's working.QuoteSo you can talk to the 8195 through the serial port and it's giving you error messages? It's been a few years since I powered mine up so I don't remember the commands. What other status commands are there? Is anything working right?You said it was 'usually' a CPU error message. Are there other error messages?I seem to remember that it took a *long* time for the alarms to clear. A quick check of the manual suggests that the minor alarm won't clear until the battery passes a daily test. Do you have that option?I'd pull the GPS receiver and bench test it rather than just buy another one. Testing would give you confidence that it was working. Buying another one, you could get another dud. What are you using for an antenna?Ed

author: K1FPV
author_rank: Contributor
timestamp: September 09, 2016, 12:12:53 pm
content: Thanks Ed! Unfortunately, I was able to replace the OnCore receiver by Motorola. Still no luck!I was able to get a second one on eBay that works great. The broken one is an earlier version and quite a bit different, so it is tough to compare the 2 receivers. I'm getting a solid 10 MHz from the oscillator, but it doesn't lock. I am not getting any GPS signal.I'm not sure but I think all the Motorola OnCore receivers use the same pin-out (10 pins) and with the new RX, I get the 1 PPS out but what the receiver does with it I'm not sure. Since Spectracom will not send me service information claiming it is proprietary, I'm stuck between a rock and a hard place. Apparently in the second working "Ageless Oscillator" I picked up, the GPS receiver is built into the main PC board.Without a schematic or service info, I'm screwed!BillK1FPV

author: edpalmer42
author_rank: Super Contributor
timestamp: September 09, 2016, 04:06:29 pm
content: Quote from: K1FPV on September 09, 2016, 12:12:53 pmHuh? AFAIK, if the GPS receiver looks different, it's a different model. There are many different Motorola Oncore receivers. Each one has different features and commands and you usually can't replace one model with another.QuoteThe M12 receiver uses a connector that's much smaller than the earlier ones. I don't know if the pinout is the same as the other models. I guess that if you were able to plug the new receiver into the connector it must be an M12 because that's the only member of the family that uses that tiny connector.Sorry things didn't work out for you. I don't have any info on the 8195 except for the user manual that you can download from Spectracom. If it's any consolation, although my unit worked and met its specifications, I wasn't impressed with its performance as a GPSDO. Instead of a nice smooth output signal, there were large frequency/phase jumps as the processor allowed the oscillator to drift off frequency and then jerked it back. It did this over and over. Ugly.Ed

author: K1FPV
author_rank: Contributor
timestamp: September 11, 2016, 10:27:39 pm
content: Thanks Ed ! I've got a Trimble Thunderbolt I compared it to and even thought I can't get the 10 MHz oscillator in the Spectracom to lock on, it is usually within a couple Hz of the Thunderbolt. I made the measurement by tying my B&K 1823A Frequency Counter into the Thunderbolt as a reference and then measured the output of the Spectracom.I honestly don't know why Spectracom won't release the service data. I understand, it is proprietary but they won't even service it as they claim it has been replaced by newer equipment. I guess they want to sell more new equipment!Bill

author: edpalmer42
author_rank: Super Contributor
timestamp: September 12, 2016, 12:02:52 am
content: 'A couple of Hertz' for a GPSDO basically means 'It's broke!'.Ed

author: K1FPV
author_rank: Contributor
timestamp: September 14, 2016, 11:56:23 pm
content: I know that Ed! That is one reason why I'm trying to fix the Spectracom receiver. Even without the unit functioning properly, the OCXO is still pretty close, so if I can get the logic system to lock up the OCXO, then it would be dead on!Right now, it is looking like the OnCor receive in the Spectracom isn't working. If I can locate a similar Motorola OnCor receiver, then perhaps I'll manage to get it to work!Bill