Seeburg STD4 selection problem

Hi, I have a Seeburg STD4 which has been working great for months now..a couple of days ago the selection system started acting up as follows; whenever I make a selection it will always play an equivalent with a number 5 as the second digit...example: If I select 100 it will play 150,,,If I select 200 it will play 250, If I select 130 it will play 150,,,If I select 131 it will play 151 etc, etc. Have checked voltages 13, 27 etc. all correct...Key pad lights correctly as you enter digits...Reset button works...Unpluged grey and black boxes and cleaned connections as well as the connectors behind the keypad..
Any assistance greatly appreciated!
Thanks,
Tonily

Tonily,
Back when Seeburg made that phono, if you had called them and spoken to one of the engineers,
you would have been told "---that can't happen--"
Re check your symptoms--play all of the matrix selections, one at a time, to see what plays (100-111-122-133-144-155--66-77-78-79). Let me know--
Ron Rich

Thanks Ron,
Sorry for my delay in responding. Here are the results (tested 3 times):
100 = 150
111 = 151
122 = 152
133 = 153
144 = 154
155 = 155
166 = 156
177 = 157
178 = 158
179 = 159
Strange as it sounds I repeated the selections first one by one, then I entered all of the selections one after the other and the results were the same. Then I entered one selection, cancelled it, and waited for carriage to stop at home position repeated this process one selection one at a time.
Once again thanks!
Tonily

Tonily,
I never saw this problem before--my guess would be the DRD-1--
Is it still sealed ? What is the warranty date on it ?
Ron Rich

Ron,
Although not at home at the momen i clearly remember the DRD1'seal being broken...I've owned this juke since June 2012. The only issue I've had with it was when I first got it...the SHP, which after been rebuilt turned out to be the best sounding juke I've owned.....I can look for date once I get home.
Thanks!
Tonily